Women, Infant, and Children (WIC) Infant-Toddler Feeding Practices Study - II (ITFPS-2)
Conditions: Breast Feeding, Infant Nutrition, Childhood Obesity, Infant Feeding Patterns, Feeding Behavior, Healthy Eating Index
Sponsor: USDA Food and Nutrition Service

Official Title of the Study:  
WIC Infant and Toddler Feeding Practices Study-2 (Feeding My Baby, A National WIC Study) 
NCT Number:  
NCT02031978 
Document Date:  
Uploaded 3/1/2021 

 
Task Order #1 
WIC Infant and Toddlers Feeding 
Practices Study – II (ITFPS-2) 
Contract No: AG-3198-B-11-0020 
Order No:AG-3198-K-11-0073 
FINAL Research and Analysis Plan  
Deliverable 7b 
Authors 
 
Suzanne McNutt, Project Director 
Gail Harrison, Principal Investigator 
Laurie May, Senior Analyst 
Janice Machado, Operations Team Lead 
Linnea Sallack, Altarum  
Nancy Weinfield, Instrument Development Team Lead 
Mark Friedman, Systems Team Lead 
September 21, 2012 
Prepared for: 
Renee Arroyo-Lee Sing 
FNS Project Officer 
 
 
Prepared by: 
Westat 
1600 Research Boulevard 
Rockville, Maryland 20850-3129 
(301) 251-1500 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
iii 
 
Table of Contents 
Chapter 
Page 
 
1 
Study Overview ...................................................................................................  
1-1 
 
1.1 
Objectives ...............................................................................................  
1-3 
1.2 
Overview of Study Design ...................................................................  
1-4 
 
2 
Conceptual Models Informing Study Analyses and Data 
Collection .............................................................................................................  
2-1 
 
2.1 
Overview ................................................................................................  
2-1 
2.2 
Conceptual Model of Breastfeeding/Early Feeding 
Practices ..................................................................................................  
2-1 
2.3 
Conceptual Model of Early Childhood Weight Gain ......................  
2-2 
2.4 
Benefits of Using These Conceptual Models ....................................  
2-4 
 
3 
Develop and Pretest Instruments.....................................................................  
3-1 
 
3.1 
WIC Participant Survey ........................................................................  
3-1 
3.2 
Key Informant interviews ....................................................................  
3-5 
3.3 
WIC Staff Survey ..................................................................................  
3-6 
3.4 
Hospital Record Abstraction Forms ..................................................  
3-6 
3.5 
WIC Administrative Records ..............................................................  
3-6 
3.6 
Local Site Profile Form ........................................................................  
3-7 
3.7 
Pre-test Instruments .............................................................................  
3-7 
 
4 
Data Collection Protocol ...................................................................................  
4-1 
 
4.1 
Overview ................................................................................................  
4-1 
4.2 
Select and Recruit WIC State Agencies and their Service 
Sites .........................................................................................................  
4-1 
4.3 
Obtain and Abstract State WIC Plans for Features Matrix ............  
4-6 
4.4 
Collect Local Site Profile Data ............................................................  
4-7 
4.5 
Conduct Key Informant Interviews ...................................................  
4-7 
4.6 
Recruit WIC Participants .....................................................................  
4-8 
 
4.6.1 
Hire and Train Westat Staff ................................................  
4-8 
4.6.2 
ITFPS-2 Recruitment Protocol ..........................................  
4-10 
4.6.3 
Recruitment and Enrollment Steps ....................................  
4-13 
4.6.4 
Pre-Test Recruitment Protocol ...........................................  
4-15 
 
4.7 
Conduct WIC Staff Surveys ................................................................  
4-15 
4.8 
Conduct WIC Participant Survey .......................................................  
4-16 
4.9 
Obtain and Abstract Hospital and Provider Records ......................  
4-18 

Contents (continued) 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
iv 
 
Chapter 
Page 
 
4.10 
Obtain and Abstract WIC Administrative Records .........................  
4-20 
4.11 
Obtain Weight and Length Measure Directly on Infants ...............  
4-20 
 
5 
Create Data Files .................................................................................................  
5-1 
 
5.1 
Data Overview ......................................................................................  
5-1 
5.2 
Data Flow and Creating the Analysis Database ...............................  
5-2 
5.3 
WIC Key Informant Data Cleaning and Editing .............................  
5-3 
5.4 
Administrative Data Cleaning and Editing .......................................  
5-4 
5.5 
WIC Staff Survey Data Cleaning and Editing...................................  
5-4 
5.6 
WIC Participant Data (non-AMPM) Cleaning and Editing ...........  
5-5 
5.7 
AMPM Response Data ........................................................................  
5-6 
 
6 
Weighting, Nonresponse Bias Analysis, Missing Data 
Compensation, and Variance Estimation ........................................................  
6-1 
 
6.1 
Overview ................................................................................................  
6-1 
6.2 
Base weights ...........................................................................................  
6-2 
6.3 
Missing Data Compensation ...............................................................  
6-4 
6.4 
Nonresponse Bias Analysis .................................................................  
6-8 
6.5 
Variance Estimation .............................................................................  
6-9 
 
7 
Analysis ................................................................................................................  
7-1 
 
7.1 
Repeating the Analyses of Past Studies .............................................  
7-1 
7.2 
Key Analytical Variables ......................................................................  
7-2 
7.3 
Main Types of Analyses .......................................................................  
7-6 
7.4 
Data Challenges .....................................................................................  
7-8 
7.5 
Specific Proposed Analyses .................................................................  
7-8 
 
8 
Analysis Reports .................................................................................................  
8-1 
 
References ............................................................................................................  
R-1 
 
 
Appendixes 
 
A 
Summary of WIC-IFPS-1 Analyses to be Repeated ......................................  
A-1 
 
B 
Proposed Analyses for Answering Each Research Question.......................  
B-1 
 
C 
Example Tables by Socio-Demographics .......................................................  
C-1 
 
 
 

Contents (continued) 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
v 
 
Tables 
Page 
 
3-1 
Topic domains collected at each WIC participant interview .......................  
3-2 
 
3-2 
Example of modular nature of variables .........................................................  
3-3 
 
3-3 
WIC Administrative records variables .............................................................  
3-7 
 
3-4 
Summary of pre-testing by instrument ............................................................  
3-8 
 
4-1 
Interview events for core and supplemental sample .....................................  
4-16 
 
5-1 
Data files overview .............................................................................................  
5-2 
 
6-1 
Weights to be prepared and delivered .............................................................  
6-5 
 
7-1 
Summary of analyses to be repeated from previous studies ........................  
7-2 
 
7-2 
Summary of analyses to be conducted ............................................................  
7-9 
 
7-3 
Proposed model specifications .........................................................................  
7-22 
 
8-1 
List of analytical reports.....................................................................................  
8-1 
 
A-1 
List of WIC-IFPS-1 report tables and figures ................................................  
A-1 
 
B-1 
Tabular presentation of research design..........................................................  
B-1 
 
C-1 
Mother’s Intention to breastfeed by socio-demographics ............................  
C-1 
 
C-2 
Percentage of mothers agreeing with statements about perceived 
benefits of breastfeeding by other background characteristics 
(repeats IFPS-I p 73) ..........................................................................................  
C-3 
 
C-3 
Percentage of mothers agreeing with statements about perceived 
benefits of breastfeeding by breastfeeding group ..........................................  
C-3 
 
C-4 
Triggers for seeking nutrition information .....................................................  
C-4 
 
C-5 
Triggers for seeking nutrition information by race/ethnicity ......................  
C-4 
 
C-6 
Triggers for seeking nutrition information by mother’s age ........................  
C-5 
 
 
 
 

Contents (continued) 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
vi 
 
Figures 
Page 
 
2-1 
Infant feeding decision model ..........................................................................  
2-2 
 
2-2 
Early childhood weight model ..........................................................................  
2-3 
 
4-1 
Data collection activities ....................................................................................  
4-2 
 
4-2 
Flow for selecting and recruiting WIC service sites ......................................  
4-3 
 
4-3 
Decision Tree for type of technology used for conducting 
recruitment interview .........................................................................................  
4-5 
 
4-4 
Recruiter and Helper hiring process ................................................................  
4-9 
 
4-5 
Recruitment flow ................................................................................................  
4-11 
 
5-2 
Data flow from sources to analysis database ..................................................  
5-3 
 
 
Attachment 
 
1 
Response to comments on Research Plan ......................................................  
A1-1 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
1-1 
 
Many important developments in recent years concerning the Food and Nutrition Service’s Special 
Supplemental Nutrition Program for Women, Infants, and Children (WIC) program necessitate 
research to understand the nutritional intake and feeding patterns of infants and toddlers in WIC, 
including those associated with early determinants of obesity, in order to design appropriate and 
effective prevention strategies aimed at improving the health of young children. These developments 
include changes in the WIC participant population, changes in the program and the environment in 
which it functions, increasing rates of obesity among pregnant mothers and the very young, growing 
numbers of WIC mothers employed outside the home, and more than 43 percent of households 
that receive WIC benefits are food insecure.1 The number of persons served by the WIC program 
has increased steadily from less than 100,000 in 1977 to almost 9 million today, of which about half 
are children age 1 to up to 5 years old and the other half about equally split between pregnant 
women and infants. In 2010, more than half of all pregnant women and their infants, and about 25 
percent of all preschool children in the United States benefited directly from the WIC program.  
 
To address this need for updated research, FNS has funded the WIC Infant and Toddler Feeding 
Practices Study (WIC ITFPS-2). The ITFPS-2 is designed to measure the feeding practices employed 
by caregivers and the nutrition outcomes of children who participate in WIC. By capturing data on 
caregivers and their children over the first two years of the child’s life, the study will inform a series 
of research questions regarding feeding practices, the impact of WIC services on those practices, and 
the health and nutrition outcomes of children on WIC. Additionally, the study will update past 
analyses to assess changes in behaviors and trends that may have occurred over the past 20 years 
since the last major study of the diets of infants and toddlers who were WIC participants was 
conducted. 
 
The study team includes several partners: 
 
 
Westat, the prime contractor, will lead the sampling, instrument design, all stages of data 
collection, and analysis associated with feeding practices and childhood nutrition. 
                                                
1 Coleman-Jensen A., Nord M, Andrews M, Carlson S. Household food insecurity in the united States. Economic Research Report #141, September 
2012. http://www.ers.usda.gov/media/884525/err141.pdf ) 
Study Overview 1 

Study Overview 1 
 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
1-2 
 
 
Dr. Gail Harrison, University of California Los Angeles (UCLA), is the Principal 
Investigator responsible for conceptual and scientific development of the study. 
 
Altarum Institute will prepare the sampling frame of WIC State and local agencies, and 
lead the instrument design and data collection associated with WIC state and local 
agency staff. 
 
Dr. Shannon Whaley, Public Health Foundation Evaluation (PHFE-WIC), will provide 
expertise in instrument design and operations. 
 
 The Center for Weight and Health, UC Berkeley, will contribute to instrument 
development and the conceptual and scientific development of child weight and health. 
 
Dr. Jane Heinig of UC Davis, and Dr. Leann Birch of Penn State University, will serve 
as consultants to provide expertise in WIC breastfeeding/nutrition education and infant 
feeding practices and baby behaviors. 
In addition to the study team, a Peer Advisory Panel (PAP) was convened to provide external 
expertise to ensure the study is temporally relevant and that the study findings will make meaningful 
contributions to FNS and to the WIC community. The six members of the PAP include Maureen 
Black, University of Maryland School of Medicine; Sally Findley, Mailman School of Public Health 
Columbia University; Laurence Grummer-Strawn, Nutrition Branch, Centers for Disease Control 
and Prevention; Suzanne Murphy, University of Hawaii Cancer Center; Zoe Neuberger, Center on 
Budget and Policy Priorities; and Peggy Trouba, office of Family Health, Nebraska Health and 
Human Services.  
 
The Research Plan is divided into eight chapters. The remainder of this chapter describes the main 
objectives and presents an overview of the study design. Chapter two, Conceptual Models 
Informing Study Analyses and Data Collection, describes the two models that drive the study 
(Breastfeeding/Early Feeding Practices and Early Childhood Weight Gain) and guide the analysis 
and modeling. The third chapter, Develop and Pretest Instruments, briefly summarizes the 
content of the data collection instruments and sources, and the plans for testing the instruments. 
The details of instrument content can be found in the Draft Database Plan (Deliverable10a) and 
Draft Instruments (Deliverable 11a); and a description of the pre-testing protocols can be found in 
the Final Pre-test Memo (Deliverable 9b). The next chapter, Data Collection, describes our 
approach for selecting and recruiting WIC State and local agencies and recruiting and enrolling WIC 
participants at service sites; and the protocol for conducting key informant in-depth interviews, web 
surveys of WIC clinic staff, and telephone interviews with WIC participants. This chapter also 
includes our methods for obtaining and abstracting birth hospital records and WIC and provider 
medical records, and our plan for directly collecting weight and length of infants/toddlers who have 

Study Overview 1 
 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
1-3 
 
left WIC and for whom we have no data. Chapter five, Create Data Files, provides an overview of 
data flow and a description of data cleaning and editing; and chapter six explains our proposal for 
Weighting, Nonresponse Bias Analysis, Missing Data Compensation, and Variance 
Estimation. Chapter seven, Analysis, lists in detail the analyses we plan to conduct that will 
compare current findings to relevant past work and to current objectives and standards; and the final 
chapter, Analysis Reports, provides a brief summary of the analytical report schedule and the 
content of each report. 
 
 
1.1 
Objectives 
The seven primary objectives for the ITFPS-2 include: 
 
 
Update results of data collected in WIC Infant Feeding Practice Study-1 (IFPS-1). 
 
Compare new findings with other major studies (WIC IFPS-1, FDA IFPS, and the 
Gerber/Nestle 2002 and 2008 Feeding Infants and Toddler Studies (FITSFITS). 
 
Assess effectiveness of different education and breastfeeding promotion approaches in 
achieving recommended feeding patterns and behaviors. 
 
Assess conditions of overfeeding, overconsumption, underfeeding, and inappropriate 
feeding. 
 
Identify nutrition education influences. 
 
Assess impact of WIC food packages on outcomes. 
 
Determine changes in maternal feeding practices and behaviors over time as infants and 
toddlers transition into or out of WIC. 
We will answer 60 research questions articulated in the RFQ to meet these objectives. Table 7-2 in 
the Analysis section presents the data source for each analytic table by topic area based on the 60 
research questions. Appendix A provides a summary of WICIFPS-1 analyses that will be repeated; 
Appendix B presents our proposed analyses for answering each research question; and Appendix C 
presents example tables by sociodemographics. 
 
 

Study Overview 1 
 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
1-4 
 
1.2 
Overview of Study Design 
The study design is heavily predicated on the designs used for IFPS-1 and FDA IFPS- II which are 
the two major previous longitudinal feeding practice studies. Building on the past longitudinal work 
maximizes the comparability between current study data and past work which facilitates assessing 
changes over time. We have also utilized aspects of the Feeding Infants and Toddlers Study (FITS) 
to address nutrition and feeding practices of toddlers. Additionally, we leverage many of the 
approaches previously used, such as rotating question modules, to ensure study efficiency. At the 
same time, we use some alternative approaches, such as onsite-recruiting of participants, to address 
challenges that occurred in the past. The current study also has a broader scope than the past 
longitudinal work in that it includes both infant and toddler feeding practices through 24 months 
and addresses new issues that have emerged such as the precursors to early childhood obesity. 
 
Our study is a hybrid design, incorporating a core longitudinal sample (the “core” sample) and a 
supplemental cross-sectional sample (the “supplemental” sample) to ensure precision in estimates at 
key time points. The core longitudinal sample of women and their infants will be enrolled in the 
study as they enroll in WIC (either prenatally or before their infant is 2.5 months old if they did not 
enroll prenatally). They will be followed until the infants are 24 months old, with up to 11 interviews 
occurring prenatally, and at 1, 3, 5, 7, 9, 11, 13, 15, 18, and 24 months. The supplemental cross-
sectional sample will also be recruited as the women and their infants enroll in WIC. This sample 
will be interviewed at four key time periods (1 or 3, 7, 13, and 24 months). We will collect birth 
hospital records and WIC record data at 7, 13, and 24 months for both samples. Concurrent with 
the start of WIC participant data collection, we will also collect data on WIC program features and 
personnel through a survey of WIC service site staff and key informant interviews at the State and 
Local levels. 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
2-1 
 
2.1 
Overview 
The research questions can be distilled to two major conceptual models that drive our study 
approach: (1) factors contributing to decisions about breastfeeding/early feeding practices and (2) 
factors contributing to early childhood weight gain and potentially subsequent obesity. These 
conceptual models do not specify every variable that contributes to key outcomes, but rather, they 
show the main causal drivers. Furthermore, the conceptual models help to guide the analysis and 
modeling by disentangling endogenous variables from exogenous variables and identifying the 
associated timing of decisions and outcomes that determine which relationships need to be 
addressed as simultaneous equations and which factors exert a lagged influence. The models also 
assist in identifying the influence path of the WIC policy variable. Each model is described below. 
The figures contain the categories of variables to be included in the models rather than an 
exhaustive list of all the potentially relevant individual variables. Chapter 7 includes a discussion of 
the variables and the Database Plan contains the complete list of variables.  
 
 
2.2 
Conceptual Model of Breastfeeding/Early Feeding Practices 
Figure 2-1 depicts a conceptual model of the factors that affect early feeding practices employed by 
WIC mothers and their associated outcomes. Developed from the literature on predictors of 
breastfeeding and decision making about infant feeding practices, this model highlights two initial 
key decision points: the intention to breastfeed and the actual decision to breastfeed. As noted in the 
model, there are four major exogenous groups of factors that influence one’s initial intentions about 
whether or not to breastfeed (1) Attitudes, beliefs, and knowledge about breastfeeding, (2) Past 
experiences and advice (3) Maternal health, and (4) Socio-demographic characteristics. Additionally, 
the actual decision to breastfeed can also be influenced by the infants’ health, and hospital practices 
related to the promotion of breastfeeding. In addition to these background and environmental 
factors, the mother’s WIC program experience (both current and previous) through education, and 
counseling support, can influence her breastfeeding intention and the decision to initiate 
breastfeeding. 
 
Conceptual Models Informing Study  
Analyses and Data Collection 2 

Conceptual Models Informing Study 
Analyses and Data Collection 2 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
2-2 
 
Figure 2-1. 
Infant feeding decision model 
 
 
 
Subsequent feeding practice decisions, such as the breastfeeding duration and the time until the 
introduction of solid foods, are heavily dependent on the initial breastfeeding decision as well as the 
infant’s response to the breastfeeding process. Subsequent feeding practices and outcomes also are 
affected by exogenous factors including one’s lifestyle decisions about such things as employment 
and child care. Finally, the mother’s WIC program experiences in terms of education, counseling 
support, and the provision of breast pumps, can affect subsequent feeding practice decisions.  
 
 
2.3 
Conceptual Model of Early Childhood Weight Gain 
Figure 2-2 depicts a conceptual model of the factors that lead to high weight and potentially early 
childhood obesity. The childhood weight model was developed based on the literature on early 
predictors of childhood obesity, showing the factors that affect a child’s risk of obesity. 
 

Conceptual Models Informing Study 
Analyses and Data Collection 2 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
2-3 
 
Figure 2-2. 
Early childhood weight model 
 
 
 
As depicted, maternal and family health characteristics along with socio-demographics affect one’s 
predisposition to obesity. Similarly, it is believed that early life experiences can affect the “wiring” of 
the brain, creating a predisposition for obesity. According to this theory, prenatal experiences and 
feeding practices during infancy can affect the child’s propensity for obesity. Although the factors 
affecting one’s predisposition to obesity (family characteristics) are largely exogenous, other factors 
such as infant feeding practices are choices and can be influenced by the WIC program. In addition 
to the factors that affect a child’s propensity for obesity, there are behavioral factors that directly 
affect the child’s weight (1) the child’s health and physical activity, (2) the child’s dietary intake, and 
(3) the feeding practices employed. 
 
The model shows how indicators of obesity can begin with prenatal and family background 
characteristics, and decisions made about first-year infant feeding. These contribute to both a 
lifetime propensity for obesity and childhood practices that promote or deter obesity. WIC has the 

Conceptual Models Informing Study 
Analyses and Data Collection 2 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
2-4 
 
opportunity to influence this process both during the infant and toddler periods, and through 
promoting healthy nutrition and behavior during childhood. 
 
 
2.4 
Benefits of Using These Conceptual Models 
Together these two models guide our study design and data collection strategy that emphasizes early 
feeding decisions and patterns and allows for a potential extension to explore the antecedents of 
childhood obesity. In line with the conceptual models that incorporate WIC influences, the 
recruitment target will be women enrolling in WIC for the first time for that pregnancy or infant. 
The majority of WIC participants enroll in WIC during pregnancy, and this approach of recruiting 
pregnant women into the study as they enroll in WIC will allow us to collect critical prenatal data on 
these women. This maximizes our ability to collect data prospectively, and to examine both 
influences of WIC services and characteristics of a group of WIC participants during pregnancy and 
infancy. This approach will also allow us to recruit women who enroll themselves or their baby after 
birth, and both to describe those families and to compare those families to the prenatal WIC group. 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-1 
 
Westat will collect data from multiple sources in order to accrue the variables needed to fit the 
conceptual models. The sources include WIC participants, State and local key informants, and WIC 
staff members who directly provide services. We will also abstract hospital and provider medical 
records; collect data from WIC administrative records; record measured weight and length on 
children; and document observational data at WIC service sites. To accomplish this we will develop 
instruments and forms for 11 WIC Participant interviews, two Key Informant interviews, one WIC 
Staff Survey, three abstraction activities, two anthropometric measurements, and one observation.  
 
On January 20, 2012 Westat delivered a Draft Database Plan - Revised (Deliverable 10a) that defines 
the variables that will be collected from each data source. On May 18, 2012 we delivered final 
versions of the three types of instruments: WIC Participant instruments, Key Informant topic 
guides, and the WIC Staff survey (Deliverable 11a).  
 
We pretested the instruments (WIC Participant interviews, Key informant interviews, and WIC Staff 
Survey) between February and May 2012 according to the testing protocol specified in the final Pre-
Test Plan Memo (Deliverable 9b), approved on February 17. Following are brief summaries of each 
of the data collection components.  
 
 
3.1 
WIC Participant Survey 
Table 3-1 provides an overview of the domains to be collected at each interview over the 2-year 
participant data collection period and Table 3-2 provides an example of the number and types of 
variables in a particular domain and our modular approach to collecting the variables.  
 
As the first table shows, the Participant interviews include nine different domains. Each domain 
contains a range of 4 to 60 variables that are loosely grouped together into “modules.” The 
checkmarks in the table indicate at which interviews at least one variable or module in each domain 
is asked. Not all modules within a domain will be asked at every interview. A complete list of the 
domains and variables within each domain can be found in the Final Database Plan (Deliverable 
10b), delivered to FNS July 10. 
Develop and Pretest Instruments 3 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-2 
 
 
Table 3-1. 
Topic domains collected at each WIC participant interview  
 
WIC participant survey 
 
Interview 
Variables by domain 
Screening/ 
Enrollment 
Baselinea 
Prenatal 
1 month 
3 months 
5 months 
7 months 
9 months 
11 months 
13 months 
15 months 
18 months 
24 months 
Socio-demographics and 
Background Characteristics 
9
9

9 9 9 9 9 9 9 
9 9 9
WIC Program Awareness and 
Utilization 


9

9

9
 
 
9
 

9
Maternal Health and Lifestyle 
9
9

9 9

9
 
 
9


9
Feeding Experience, Knowledge, 
Attitudes, Beliefs, Information, 
Advice 

9 9 9 9 9 9


9 9

9
Hospital Feeding Related Practices 


 
9









Current Feeding Practices 
 
 

9 9 9 9 9 9 9 
9 9 9
Child Health Behavior and Child 
Rearing Practices 


 
9 9 9 9 9 9 9 
9 9 9
Contact Updates 


9 9 9 9 9 9 9 9 
9 9 9
New Caregiver Characteristics 
 
 
 
* 
* 
* 
* 
* 
* 
* 
* 
* 
* 
a Questions will be asked at the first interview (could be prenatal, 1 month, or 3 month) 
* These questions will be asked anytime someone permanently replaces the mother as the primary caregiver 
 
The second table (Table 3-2) provides an example of our modular approach, in which we distribute 
questions across interviews in order to spread overall participant burden out across interviews. This 
table presents the Socio-demographic and Background characteristics domain which contains 33 
variables. We have structured the domain such that questions are asked when they are most relevant, 
and are only repeated when they are needed. 
 
 
Of the up to 22 questions indicated for the Screening/Enrollment or Baseline 
interviews,2 a module of 9 will not be asked again during the study either because the 
responses will not change, or because they are intended only to indicate status at the 
outset of the study (i.e., mother DOB, race/ethnicity, US born, parity, and prior WIC 
receipt,  
 
Similarly, maternal employment during pregnancy is asked only once, at 1 month. 
 
 
                                                
2 Of note: the baseline interview could be the Prenatal, the 1-month, or the 3-month interview, depending on when the mother was recruited. 
Furthernore, the screening/enrollment interview takes place on site and is not part of the prenatal, 1-month, or 3-month interviews. 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-3 
 
Table 3-2 
Example of modular nature of variables 
 
Variables by Domain 
Enrollment/ 
Screening 
Baselinea 
Prenatal  
1 month  
3 months 
5 months 
7 months 
9 months 
11 months 
13 months 
15 months 
18 months 
24 months 
Socio-demographics and Background Characteristics 
Maternal birth date 
9












Maternal ethnicity 
9












Maternal race 
9












US or foreign born 

9











Marital status 

9







9 


Parity 

9











Interpregnancy interval/interpartum 
period 

9











Number of children in household 

9











Due date, if enrolled prenatally 
9
 
 
 
 
 
 
 
 
 
 
 
 
Infant DOBb 
[9] 
 
 
[9] 
 
 
 
 
 
 
 
 
 
Single or multiple birthb 
[9] 
 
 
[9] 
 
 
 
 
 
 
 
 
 
Child nameb 
[9] 
 
 
[9] 
 
 
 
 
 
 
 
 
 
Child sexb 
[9]

 
[9] 
 
 

 
 

 


Child ethnicityb 
[9]

 
[9] 
 
 

 
 

 


Child raceb 
[9]

 
[9] 
 
 

 
 

 


Respondent still caregiver/new 
caregiver information 
 
 
 
9 
9 
9 
9 
9 
9 
9 
9 
9 
9 
New pregnancy/due date 


 
 
 
 
9
 
 
9  
9

Household size 
9

 
 
 
 
9
 
 
9  

9
Household income 
9

 



9


9 

9
Presence of infant's father 

9







9 


Receipt of public assistance 

9
 
 
 
 

 
 
9  

9
Brief household food insecurity 


 
 
 
 
9
 
 
9  


6-item food insecurity 


 
 
 
 
 
 
 
 
 
 
9 
 
 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-4 
 
Table 3-2 
Example of modular nature of variables (continued) 
 
Variables by Domain 
Enrollment/ 
Screening 
Baselinea 
Prenatal  
1 month  
3 months 
5 months 
7 months 
9 months 
11 months 
13 months 
15 months 
18 months 
24 months 
Socio-demographics and Background Characteristics 
Use of emergency food sources 












9
Prior WIC receipt 

9











Number of prior children on WIC 

9











Duration of prior WIC receipt (mother 
and/or children total years) 

9











Educational attainment 

9










9
Current educational status 




9

9


9  9
9
Employment during pregnancy 



9









Current employment status 




9

9


9  9
9
Age of child when mother began 
school or workc 
 
 
 
 
[9] 
 
[9] 
 
 
[9] 
 
[9] 
[9] 
Continuation/discontinuation of WIC 
participation 
 
 
 
9
9 9 9 9 9 9 9 9
9
Location of WIC service receipt 
 
 
 
9
9 9 9 9 9 9 9 9
9
If WIC discontinued, age of child 
when WIC discontinued 
 
 
 
9
9 9 9 9 9 9 9 9
9
If WIC discontinued, reasons for 
leaving WIC 
 
 
 
9
9 9 9 9 9 9 9 9
9
a Questions will be asked at the first interview (could be prenatal, 1 month, or 3 month) 
b Asked at enrollment if enrolled in study after child’s birth; asked at 1 month if enrolled in study prenatally. The bracketed checks 
indicate times when this could be asked conditional upon time of enrollment. 
c Asked the first time postnatally that the mother reports that she is currently working for pay. The bracketed checks indicate times 
when this could be asked. 
 
 
Some variables are asked only once during the study, but the timing is conditional upon 
participant characteristics such as questions asked at either enrollment/screening or 1 
month depending on whether the mother is a prenatal or postnatal enrollee (i.e., due 
date, infant DOB, single or multiple birth, child name, child sex, child ethnicity, child 
race); the age of the child when the mother returned to work, asked the first time 
postnatally the mother reports currently working for pay; or questions about timing and 
reasons for leaving WIC, asked when the mother indicates she no longer receives WIC. 
 
Other variables will be asked periodically over the course of the 24 months to capture 
changes over time (i.e., marital status, new pregnancy, household size, household 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-5 
 
income, presence of infant’s father, receipt of public assistance, household food 
insecurity, educational attainment, educational status, and employment status).  
 
Only a small number of variables will be asked at every post-birth interview, as current 
status is required for each interview (i.e., respondent still the child’s caregiver; 
continuation/discontinuation of WIC receipt; location of WIC service receipt) 
The complete list of domains and variables can be found in the Database Plan (Deliverable 10b) 
delivered on September 7, 2012. 
 
 
3.2 
Key Informant interviews 
There will be two key informant interview guides: one for state agency personnel and the other for 
local personnel. These interviews will confirm and supplement information extracted from State 
WIC Plans and local Nutrition Education Plans, to clarify state and local policies related to infant 
feeding, and to create profiles of local agencies for use in analyses. The key informant interviews will 
be framed by a hard copy topic guide that will be cross-matched to the research questions and 
analysis plan. The topic guide will include both open and closed-ended questions, along with follow-
up probes to clarify and amplify responses. 
 
These in-depth interviews will collect information about data included in the state’s information 
system and how those data are used at the state and local level. In addition, the interviews will ask 
about policies regarding the content and timing of breastfeeding education and support, the 
qualifications and training of staff that provide nutrition and breastfeeding education and support, 
type of infant feeding information provided to participants, the use of breastfeeding peer counselors, 
policies for providing breast pumps and whether there are special breastfeeding promotion 
initiatives. In addition, we will ask about the policy and practice related to prescribing food packages 
including supplying any formula in the first month for breast-fed babies, and the content of 
educational materials. We will also obtain information about staffing, including local staffing 
characteristics and roles features (e.g., certifier, nutrition educator, clerical) use of professional and 
paraprofessional staff; length of WIC tenure of each staff member; number of staff performing 
different roles and training on infant nutrition, breastfeeding and nutrition educator skills provided 
to local staff. We expect these interviews will take about 60 minutes to complete. 
 
 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-6 
 
3.3 
WIC Staff Survey 
We will develop a WIC Staff Survey to obtain information about the local WIC programs and the 
training and experience of the staff. In developing this survey, we will draw on some of Altarum’s 
current work to collect similar information from WIC staff in the Midwest and Mid-Atlantic WIC 
State agencies. The survey will be programmed as a web-based instrument, but also prepared as a 
hard copy questionnaire for those who do not have Internet access. The survey will include 
demographic questions about WIC staff persons, including length of tenure at WIC, age range, 
education and training about their WIC related training and experience; and about their knowledge, 
attitudes, and beliefs about (1) breastfeeding and infant/toddler nutrition, (2) WIC foods, and (3) 
policies and approaches for providing nutrition education and breastfeeding support services. These 
interviews will take approximately 30 minutes to complete.  
 
 
3.4 
Hospital Record Abstraction Forms 
We will develop medical record abstraction forms to capture hospital birth data, including infant 
birth weight/length, gestational age, Apgar score, head circumference, infant time in NICU, blood 
tests, amount of wet/soiled diapers, birth complications, type of delivery, and if infant fed other 
than human milk in hospital. In addition, an abstraction form will be developed to collect 
length/weight and date of measurement from child healthcare provider records. Finally, we will 
design a form for home health service staff to directly measure length and weight on infants in their 
home who do not have a health care provider. We plan to use standard forms from the National 
Health and Nutrition Examination Survey (NHANES) to document direct measures of 
length/weight. This will require the staff person to measure the child 2-3 times and document each 
measurement.  
 
 
3.5 
WIC Administrative Records 
We will design data entry forms so the Westat research team can easily abstract data from WIC 
administrative records to capture information on maternal and infant/toddler characteristics at 
multiple points in time throughout the data collection period. Data to be collected on the mothers 
and children are listed below.  
 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-7 
 
Table 3-3. 
WIC Administrative records variables 
 
WIC Administrative 
Variables 
Enrollment 
Prenatal  
1 month  
3 months 
5 months 
7 months 
9 months 
11 months 
13 months 
15 months 
18 months 
24 months 
Maternal Characteristics 
Food package prescribed 
9 
 
9 
 
 
9 
 
 
 
 
 
 
Infant/Toddler Characteristics 
Weight and date 
 
 
 
 
 
9 
 
 
9 
 
 
9 
Length and date 
 
 
 
 
 
9 
 
 
9 
 
 
9 
Food package prescribed 
9 
 
 
 
 
9 
 
 
9 
 
 
9 
 
 
3.6 
Local Site Profile Form 
Altarum will develop a Local Site Profile form to document observational information about each 
service site at the onsite visit. The form will also be used to record information available from 
existing State and local reports and records, and to directly collect information from local site staff. 
The form will collect a variety of information, including the organization of the local WIC site, site-
level participant demographics, services the sites provide, food packages available, and community 
resources, appointment scheduling protocols, availability of breast pumps. 
 
 
3.7 
Pre-test Instruments 
As shown in Table 3-4, three types of instruments were pre-tested in February-May, 2012. All testing 
was done with 9 or fewer English and Spanish-speaking respondents. Using standard cognitive 
testing methodology, respondents were asked to answer the questions in the interview and the 
methodologist probed with follow-up questions to assess whether the question intent was clear, the 
terminology well-defined, and the responses unambiguous. We evaluated the length of the 
interviews to ensure the respondent burden was reasonable. Instruments were revised as needed and 
problematic questions retested. The details of the pre-testing plan are presented in the Final pre-Test 
Plan Memo (Deliverable 9a) delivered to FNS on January 20 and approved on February 17, 2012. In 

Develop and Pretest Instruments 3 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
3-8 
 
addition, on May 6 Westat delivered the pre-testing results of a number of questions specified by 
FNS. 
 
Table 3-4. 
Summary of pre-testing by instrument 
 
Instrument 
#Respondents 
Recruitment location 
Protocol 
WIC 
Participant 
Interview 
Total: ≤9/round 
English: Sites in West, 
South, Midwest, and East 
Coast 
Spanish: NY, FL, and LA 
 
Phase 1: internal expert review 
 
Phase 2: telephone interview 
 
 
 
 
 
Key Informant 
topic guides 
Total: 8 
Per state: 2 (state 
official & local 
nutrition professional) 
4 states in different USDA 
regions 
 
Topic guide & interview 
protocol mailed 
 
Telephone interview 
 
 
 
 
 
WIC Staff 
Survey 
Total: ≤9  
 
4 local agencies on East & 
Westat coasts 
 
Hard copy mailed 
 
Phone or in-person interview 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
4-1 
 
4.1 
Overview 
Over the 3-year data collection period3 the Westat team will conduct 11 key data collection activities 
to collect the information needed to answer the research questions represented by the causal models. 
These are summarized in Figure 4-1 in the sequence in which they occur. The details of each activity 
are described below. 
 
 
4.2 
Select and Recruit WIC State Agencies and their Service 
Sites  
Westat will draw the sample of WIC service sites in a 2-phase process. First we will sample 160 WIC 
sites from the PC 2010 data. Altarum Institute will work with State and local agencies to obtain 
available information for each of the 160 sites, including average number of participants served at 
the site each month, average number of new prenatal and postnatal enrollees in the most recent 
month, the days of the week/month when enrollments are performed, and type of site (e.g. 
permanent, satellite, mobile). Since some of the sites in the first phase of sampling will be local 
agencies comprised of multiple service sites, Altarum will work with States to identify which are 
single service sites and which are a composite of multiple service sites. When a selected site is 
determined to be a composite of multiple sites, the State will be asked to provide a list of the single 
service sites in the composite and the publicly available information described above for each.  
 
In the second phase of sampling Westat will use the information collected by Altarum to sample 80 
sites. To be selected, the site will need to meet certain minimum criteria before they can partner with 
the ITFP-2 team. In particular each site must be a currently active site and enroll (on average) a 
minimum of 1.5 pregnant women/infants per day. If a site does not meet these criteria it will be 
replaced. Altarum Institute will enlist the cooperation of the 80 sampled sites through telephone and 
web meetings with State, local and WIC service site officials. Figure 4-2 illustrates the selection and 
                                                
3 Westat will collect data over a 3-year period, but the length of time a mother will be a participant is dependent on when she was recruited. Mothers 
reruited when they were 1-month pregnant will be participants for 2.7 years while mothers enrolled when their baby was 2.5 months old will be in 
the study for about 1.8 years. 
Data Collection Protocol 4 

 
 
Data Collection Protocol 4 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
4-2 
 
Figure 4-1. 
Data collection activities 
 
ID
Data collection activity
Start
Finish
2015
Q4
Q4
Q2
Q4
Q1
Q3
Q4
Q2
Q3
Q1
Q2
Q1
5
5/31/2013
1/9/2013
Enroll women at WIC sites
6
3/29/2013
2/1/2013
Conduct WIC clinic surveys
2014
2012
Q2
9
3/31/2016
4/30/2013
Obtain/abstract mother/infant WIC 
records
2013
Q3
4
3/29/2013
1/1/2013
Conduct key informant interviews
Mode
In-person, phone
In-person, phone
Web, hard copy
Mail, email, fax
Duration
3 mo
4.5 mo
2 mo
35 mo
Q3
Q3
2016
Q1
Q2
11
35 mo
3/31/2016
4/30/2013
In-person
Obtain weight/length measurements 
directly on infants
8
37.5 mo
2/29/2016
1/21/2013
Phone
Conduct WIC participants interviews
2
6 mo
12/31/2012
7/2/2012
Mail, email, web
Obtain/abstract State WIC plans for 
Information Systems Profile & 
Features Matrix for 80 sampled sites
3
5.5 mo
3/29/2013
1/1/2013
In-person, phone, 
email
Collect selected site profile data
Mail, email, fax
Obtain/abstract mother/infant 
records from providers (those 
dropped out of WIC)
10
35 mo
3/31/2016
4/30/2013
Mail, email, fax
Obtain/abstract mother/infant 
records from providers (those 
dropped out of WIC)
1
2 mo
6/22/2012
4/9/2012
Phone, email
Request available information from 
160 sampling units
7
14.5 mo
3/20/2014
1/10/2013
Mail, email, 
phone, fax
Obtain/abstract birth records

Data Collection Protocol 4 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
4-3 
 
Figure 4-2. 
Flow for selecting and recruiting WIC service sites 
 
Draw  160 Sampling Units 
(Composite Sites/Agencies & Individual Sites)
By 3/23/2012 
Visit 80 Sites to Finalize Site Details
 (Complete Local Site Profile, Conduct Select Key Informant Interviews)
Beginning 1/1/2013 through 3/31/2013
 Prepare Memo for Each State Agency Summarizing Logistics 
for All Sites in State
Beginning 11/9/2012 through 2/8/2013
Request Available Information for 160 Sampling Units from State Agencies
(2 Stage Process) 
Phase 1: Obtain list of sites within a composite site/agency, confirm site is currently in 
operation and has no plans to close before the enrollment period ends, determine if site 
enrolls participants offsite 
Phase 2:  Obtain enrollment count for one month and enrollment days for sampled site as 
a whole and approximate distribution of enrollment and enrollment days by location)
From 4/1/2012 through 6/15/2012
Conduct Webinar and Create Webinar Archive
By 8/1/2012
Select Alternate 
Matched Site
From 8/10/2012 
through 10/1/2012
Agree to 
participate?
Send Recruitment Letters and Q&As to State Agencies and 80 Sites
Beginning 7/15/2012
Select 80 Sites Using Information Provided by State Agencies
Matched Alternative sites selected by 7/31/2012 
By 7/15/2012
Discuss Site Participation with Each of 80 Sites and their State Agencies
Begin to obtain information for Local Site Profile 
Determine preliminary recruitment and staffing plan for site
From 8/8/2012 through 10/26/2012
Randomize Windows
10/31/2012
Yes
Conduct Local Staff Survey
2/8/13 through 4/30/2013
No
 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-4 
 
recruitment process of the sites. The recruitment of State agency directors will begin with a 
communication containing an advance letter, study fact sheet, answers to anticipated questions, and 
an invitation to participate in a 1-hour webinar (30-40 minutes for the presentation followed by a 
Q&A session of about 30 minutes). A follow-up letter will list the sampled sites under each State 
and will inform directors that they can invite key staff from the sampled local agencies and service 
sites to the webinar. The webinar will be recorded and be made available to those who could not 
attend the live session. During the webinar, Altarum will elaborate on information provided earlier 
and answer questions from those who participate. State agencies will be invited to be partners in the 
ITFPS-2 and State directors will be asked to assist with gaining the cooperation of their sampled 
sites. Approximately a week after the webinar, Altarum will begin to work with the States to finalize 
site participation details and to begin to compile a Local Site Profile Form for each site. The profile 
will include information such as hours of operation, percent of Spanish speaking participants and 
other information available from the State agency or local site. Altarum will summarize these details 
in a written communication with copies provided to the State agency, local site, and FNS. If a site 
requests, Altarum will prepare a memorandum of understanding (MOU).  
 
In order to be chosen to participate in the ITFPS-2, a service site will need to identify all eligible 
WIC enrollees every day of the enrollment window. An eligible WIC enrollee is an English or 
Spanish speaking woman who is (1) pregnant and is enrolling in the WIC program for the first time 
for the current pregnancy; or (2) was not enrolled prenatally but is enrolling her infant who is less 
than 2.5 months old. We will consider sampled sites that cannot commit to identifying eligible 
women to be non-responders to the ITFPS-2.  
 
Once sites are recruited Westat and Altarum staff will have multiple telephone conversations with 
the sites to work out the best arrangements for recruiting new WIC enrollees in that site. We will use 
one of two recruitment models in each site: either staff a Westat field recruiter or a Westat helper 
to recruit new enrollees into the study. The field recruiter’s responsibility will be to explain the study 
to each new WIC enrollee and conduct the screener and enrollment interview using a laptop 
computer. The Westat helper’s responsibility will be to explain the study and connect the new WIC 
enrollees to a Westat recruiter by cellphone. Our preferred staffing arrangement is to use a field 
recruiter since the recruiter can build more rapport while talking with the new enrollees in-person, 
and will more often be able to enroll the woman immediately into the study.  
 
As shown in Figure 4-3, we will determine the best technology for conducting the recruitment 
interviews, which will partly influence the staffing model we use in a particular site. If a site has 
WiFi, accessible ethernet connectivity, or cellular coverage we can staff the site with a Westat field  

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-5 
 
Figure 4-3. 
Decision Tree for type of technology used for conducting recruitment interview 
 
Westat explains Site Recruitment 
Does site have 
WiFi?
Can site 
accommodate 
a Westat field 
Recruiter?
Does site 
have 
connectivity 
via ethernet 
cable?
Can Westat 
access 
internet?
Does site 
have cellular 
coverage?
No
Yes
No
No
Conduct 
recruitment
(On-site recruiter 
or telephone 
recruiter)
Does site 
have cellular 
coverage?
WIC sends completed referral 
forms to Westat via 
secure communications
No
No
yes
Yes
Yes
Use Westat 
Helper Model
No
Yes
Yes
 
 
recruiter. If a site indicates they do not have enough space or privacy for a Westat field recruiter to 
have a two-way conversation with a WIC enrollee, but could accommodate a Westat person handing 
a phone to the woman for a one-way conversation, we will use the helper model. The helper will 
escort the woman to the pre-determined designated private space, hand the phone to the woman, 
and leave the area so she will have privacy. The Screener/Recruitment interview contains no 
sensitive questions and all responses are closed-ended; when answered by phone they will require 
the following responses: “yes/no,” numbers, names, and contact information. If by chance, 
someone overhears a piece of the phone conversation, the responses will not be meaningful. If the 
participant does not fee there is enough privacy, she will be given the option to have the recruiter 
call her at a later time. If there is no cellular coverage we cannot accommodate either model and will 
request the WIC staff keep a referral form on each new enrollee (discussed in Section 4.5.3) and 
send to Westat on a regular basis in a secure communication mode (i.e., secure fax, encrypted email, 
or tracked mail).  
 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-6 
 
To date 76 sites have indicated they have private space to accommodate a recruiter interviewing a 
respondent. Some sites have indicated the recruiter may have to move from space-to-space 
throughout out the day, but at any one time there will be private space to conduct an interview. 
Based on earlier conversations with the other 4 sites, we believe they will be able to provide private 
space to accommodate a recruiter as well. We expect to talk with the remaining 4 sites before 
November 1 and will update this information at that time.  
 
Once recruitment begins a site may change its mind if it prefers a different type of Westat field staff. 
This will not be difficult to accomplish since we plan to train the recruiters and helpers on the same 
procedures. Altarum and Westat will also talk with the sites about options available to accommodate 
privacy for women who are being screened and recruited for the study. We understand that WIC 
sites are generally set up to provide space where WIC staff can talk to women and share confidential 
information even when clients and staff are visible to others. We will defer to the sites’ 
recommendations as to the best way to accommodate a 15-20 minute recruitment interview. 
However, in order to ensure that the participant has been determined to be eligible for WIC and to 
make sure that there is no impact (real or perceived) of the study on the receipt of WIC benefits, the 
determination and flagging will occur at the end of the participant’s WIC appointment. Westat will 
not approach the participant until she has completed all of their WIC business. The recruitment 
should not interfere with or interrupt any participants being certified, receiving benefits, or receiving 
nutrition education or breastfeeding support. For example, this includes interruptions or delays to 
the flow of WIC appointments and being approached in the waiting room when WIC business has 
not been completed. Furthermore, the recruitment will not, directly or indirectly, impact or change 
clinic hours (example: M-W, 8am-5pm) or clinic schedules (example: M-W are certification appts, 
Thu-Fri are nutrition education).  
 
 
4.3 
Obtain and Abstract State WIC Plans for Features Matrix 
During the recruitment period, Altarum staff will request from each State agency available 
documents, including State plans, State program policy manuals, State nutrition education plans, and 
descriptive information about the State’s information systems to complete the Information system 
profile and Features matrix. The Information System Profile and Features Matrix will be used to 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-7 
 
determine the source and protocol for obtaining data from WIC administrative records for 
participants enrolled in the study. These are expected to include weight and length measures for 
infants and toddlers and food package prescription for mothers and babies. It will also be used to 
compile information about policies and features of nutrition education and breastfeeding services 
provided by the State agency and sites in the State.  
 
 
4.4 
Collect Local Site Profile Data 
Altarum will collect Local Site Profile for each site during an onsite visit using information collected 
from State and local agencies, as well as observational data and interaction with staff during the site 
visit. The Site Profile will inform the communication and coordination with the service sites and will 
provide information about site operations and policies.  
 
The onsite visit will be scheduled in the January-March timeframe, 2013. The visit will be conducted 
by Altarum Institute staff members who will be assigned as study regional coordinators to 
coordinate study activities with the site and to conduct the data collection (key informant interview 
and site profile). The visit will take approximately three hours. During the visit, the regional 
coordinator will conduct the key informant interview (which will include requesting information 
such as the appointment schedule template)., provide an overview of the staff survey, and respond 
to questions about study activities. The information for the local site profile will be collected 
through observation, (e.g. count the number of staff working at the site, record the hours of 
operation posted). We estimate the burden to complete the key informant interview will be 
approximately 1 hour of time. The remainder of the three hours will be used to observe the clinic 
activities and answer staff questions about the study.  
 
 
4.5 
Conduct Key Informant Interviews  
Following OMB approval, Altarum staff will conduct key informant interviews with one State 
agency representative and one service site staff person for each State and site selected for the study. 
One key informant interview will be conducted per State agency regardless of the number of service 
sites selected in the State. The decision regarding who completes the interview will be made by the 
State Agency WIC Director. We will send the questions to the State Agency in advance of 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-8 
 
scheduling the appointment. The interviews with State agency staff members will be conducted by 
telephone.  
 
The key informant interview at the local level will most likely be with the site supervisor or 
coordinator or whoever is identified as the most knowledgeable about the nutrition education and 
breastfeeding policies, procedures, and staffing at the site. We will work with the State agency and 
the administration of the local site, e.g., local agency WIC director or manager, to determine the 
most appropriate person to interview. Interviews with the staff members at each service site will be 
conducted face-to-face. All interviews will be recorded for quality control purposes. If needed, a 
staff person from the local agency that oversees the site will be contacted in-person or by phone to 
respond to any questions the staff person at the service site could not answer. This interview will 
take approximately one hour to complete with each State and local key informant. 
 
 
4.6 
Recruit WIC Participants 
Over a 5 month period beginning in January 2013 Westat will screen about 98 new WIC enrollees at 
each of 80 selected WIC service sites during a pre-determined enrollment period. The new enrollees 
will include prenatal mothers and postnatal infants <2.5 months old (whose mothers were not 
enrolled prenatally) who are enrolled at the service site or at outreach locations (hospital, mall, 
satellite sites) by staff in the service site. We expect to recruit about 55.4 new enrollees per site. The 
80 WIC sites will be of varying sizes and therefore have vastly different enrollment flows (from 1.5 
new enrollees per day up to 14 or more new enrollees per day). To accommodate the differences in 
enrollment flow the recruitment window at each site will range from 7 to 66 days (about 1 to 13 
weeks). The enrollment start dates will be staggered and slightly frontloaded to ensure the sites with 
longer windows begin enrollment early in the period. Details of the sampling process can be found 
in the Final Sampling Plan in Deliverable 8b, submitted to FNS on February 17, 2012. Following is a 
description of our process for recruiting and training Westat staff, and a discussion of the steps in 
recruiting new WIC enrollees into the ITFPS-2. 
 
 
4.6.1 
Hire and Train Westat Staff 
As discussed above, we will staff the WIC sites with either Westat recruiters or helpers to conduct 
the ITFPS recruitment process. We expect many of the field staff will come from Westat’s nation-

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-9 
 
wide pool of several thousand part-time and fulltime field data collectors who are routinely trained 
for specific requirements of a study. For sites for which we don’t have field staff living in the area of 
a WIC site, we will plan to hire locally. As illustrated in Figure 4.4, we will first ask WIC staff for 
referrals (e.g., friends, family, part time WIC employees, or past WIC employees). Part-time WIC 
employees who apply for a position must request approval from their local and State agency before 
Westat can hire them. If we don’t find staff in that manner we will advertise in the local area or hire 
from temp agencies in the local area.  
 
Figure 4-4. 
Recruiter and Helper hiring process 
 
Interview and hire 
local data 
collectors
Advertise
Hire as Westat staff
Temporary
Agency
Do Westat field files 
have experienced 
data collectors 
available in this 
location?
Yes
Does WIC office have 
recommendations for 
local hires?*
No
Yes
No
Yes
Qualified 
applicants?
Yes
No
Qualified 
applicants?
*local hires may include candidates who work for WIC part-time.  Westat would consider employing these candidates during 
their off-duty hours.  Potential candidates must request approval from their local and State agencies
 
 
The sites will begin recruitment on a rolling basis over a 9-week period. Westat will conduct 9 
trainings with the field recruiters; each training will begin approximately 1-2 weeks before 
recruitment begins at each site. The training will be conducted using 25 self-paced training modules, 
real-time Webex sessions, and role plays. It will cover procedures to introduce the study to the 
potential WIC participant, gain their cooperation, connect potential enrollees with the Westat TRC 
center (helpers training), and how to work collaboratively with the local WIC site staff. Trainees will 
be required to complete a summary quiz at the end of the self-paced LMS training. They will be 
asked to review the materials and retake the summary quiz until they score with 100 percent 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-10 
 
accuracy. This is a requirement before participating in the WebEx training sessions. Trainees will be 
monitored during the WebEx training role plays and corrective action will be provided. Following 
the WebEx training, trainees will be paired together in dyads to practice introducing the study and 
obtaining cooperation through scripted role plays. Trainees must demonstrate mastery of the contact 
procedures to the observing trainers in order to be approved to work on the study. 
An important training module that all interviewers will receive is how to maintain confidentiality 
when collecting data or assisting a respondent in completing an interview. In addition, all Westat 
employees will sign a confidentiality agreement annually to ensure they understand what is 
considered confidential, the importance of privacy, and how to maintain confidentiality. Finally, 
finding space in the WIC sites that offers some privacy will be an important aspect of ensuring 
participants’ responses are kept confidential.  
 
 
4.6.2 
ITFPS-2 Recruitment Protocol  
The sites will begin recruitment on a rolling basis over a 9-week period. In the 1st week we will 
launch recruitment in 5 sites, in the 2nd-8th week we will launch in 10 sites weeks; and in the 9th week 
we will launch in 5 sites. Recruitment will be conducted over a 4.5 months. Figure 4-5 illustrates the 
recruitment protocol. The first step will be for a WIC staff person to identify a new WIC enrollee. 
From talking with the sites we understand that this will be a simple process for staff particularly 
because these participants have to be enrolled into the management information system. Based on 
our discussions with sites and Altarum’s experience working with WIC programs in 31 States and 
over 200 clinics, we understand that the WIC enrollment process in most sites starts with a WIC 
staff person obtaining key information from the person seeking to enroll. This includes household 
family size and income, residence, and identification. The staff person will assess the income and 
residence information to determine if the applicant meets income and residence/service area 
requirements. The applicant will then participate in a nutrition assessment, including anthropometric 
and blood tests, to determine nutritional risk and, if they are determined eligible for the WIC 
program they will receive nutrition education and a food package. If the enrollee comes into the 
service site to enroll, the WIC staff person will identify all pregnant women in the designated study 
enrollment window who are enrolling in WIC for the first time for their current pregnancy and all 
infants less than 2.5 months whose mothers did not enroll prenatally. They will complete a 2-ply 
referral form that includes WIC ID, name, contact information, pregnancy status, age, and language. 
One copy will go to the woman (yellow); the other will be saved for the Westat recruiter/helper who 
will collect the forms at the end of the day. The Westat recruiter/helper will look for women holding 
a yellow referral form and attempt to intercept her at the end of her WIC visit in order to introduce  

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-11 
 
Figure 4-5. 
Recruitment flow 
 
 
Step 1
WIC staff person 
Identifies  New Enrollee
(English/Spanish speaking Prenatal Mother 
or an Infant <2.5 months old)
Steps 4 & 5
Westat Telephone Recruiter
Administers Screener
Step 6
Westat Telephone Recruiter
Obtains Consent & HIPPA
Copy will be sent to participant
Step 9
Westat Home Office
Sends study materials, consent/HIPPA, 
incentive, and cellphone (if needed) to 
participant
Step 3
Westat Field Staff
(Recruiter or Helper) 
Introduces study
Steps 4 & 5
Westat Field Recruiter
Administer Screener 
Eligible?
Step 7
Westat Telephone Recruiter
Administers Enrollment Screener
Step 6
Westat Field Recruiter
Obtains Consent & HIPPA
Gives copy to participant
Eligible?
Step 7
Westat Field Recruiter
Administers Enrollment Screener
Step 8
Westat Field Recruiter
Determines if participant needs 
cellphone
END
Step 8
Westat Telephone Recruiter
Determines if participant needs 
cellphone
Step 2
Intercept 
onsite?
Available?
Westat Field Staff
(Recruiter or Helper)
Collects contact information
Interested?
Westat Telephone Recruiter
Contacts new WIC enrollee
Yes
Interested?
Yes
No
Yes
Yes
No -- Helper links to telephone recruiter
No
END
No
END
No
No
WIC enrollee 
take flyer?
Call in?
No
Yes
No
Recruiter?
Yes
Yes
Yes
 
 
 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-12 
 
the study and screen the woman.. The strategy for notifying the recruiter/helper will be refined at 
each site, but the basic method is to have the Westat field recruiter/ helper look for the women with 
a yellow referral form and talk to them about the study once WIC business is conducted. In order to 
ensure that the participant has been determined to be eligible for WIC and to make sure that there is 
no impact (real or perceived) of the study on the receipt of WIC benefits, the determination and 
flagging will occur at the end of the participant’s WIC appointment. Westat will not approach the 
participant until she has completed all of their WIC business. The recruitment should not interfere 
with or interrupt any participants being certified, receiving benefits, or receiving nutrition education 
or breastfeeding support. For example, this includes interruptions or delays to the flow of WIC 
appointments and being approached in the waiting room when WIC business has not been 
completed. Furthermore, the recruitment will not, directly or indirectly, impact or change clinic 
hours (example: M-W, 8am-5pm) or clinic schedules (example: M-W are certification appts, Thu-Fri 
are nutrition education). 
 
Once a Westat field staff (recruiter/helper) makes contact with the woman they will find a pre-
determined private place, and introduce the Feeding My Baby Study by showing the woman the study 
flyer. In addition they will explain that to participate in the study the woman will need to answer 
some questions that day and will be contacted by phone periodically to answer some questions 
about her baby’s food consumption and feeding habits, until her child is two years old. The 
recruiter/helper will tell the woman that if she is confirmed to be eligible for the study, the interview 
today will take about 20 minutes and she will be compensated $50; all future telephone calls will take 
no more than 30 minutes, and she will be compensated $20 for each telephone interview. If the 
woman is interested and has time to spend talking about the study, she will be interviewed 
immediately in service sites that have a recruiter. In sites that have a helper, the helper will explain 
that the woman will be connected to a Westat telephone recruiter who will provide more detail 
about the study and will ask her some questions. The recruitment interview will take 20 minutes and 
the woman will be mailed $50 for her time. Women who are interested but don’t have time to spend 
at the clinic will be asked by the Westat field staff person for a good time and way to contact them 
to talk about the study. That information will be transferred to a Westat telephone recruiter who will 
contact them by phone.  
 
The Westat recruiter (field or telephone) will administer a recruitment screener to determine whether 
the woman is eligible, and if so will obtain her consent and explain the HIPAA form and the need 
for a signature. They will administer the enrollment interview and obtain an address to send the 
incentive and study materials, and a telephone number to contact the participant for the follow-up 
interviews. If a woman cannot provide a contact telephone number the recruiter will ask if she needs 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-13 
 
a cellphone. The Westat home office will send study materials, a cellphone (if needed), and the study 
incentive.  
 
We expect there may be a very small number of women who will be enrolled in locations other than 
at the service site (e.g., hospital, mall, mobile vans). In those cases, the WIC staff will fill out a 
referral form and the Westat recruiter/helper will send the information to Westat. A Westat 
telephone recruiter will contact the woman.  
 
 
4.6.3 
Recruitment and Enrollment Steps  
Participant enrollment at the service site is presented in Figure 4.5, and described below. 
 
1. 
Identify Eligible WIC Enrollees. WIC staff will identify all pregnant women in the 
designated study enrollment window who are enrolling in WIC for the first time for 
their current pregnancy and all infants less than 2.5 months whose mothers did not 
enroll prenatally. They will complete a 2-ply referral form that includes WIC ID, name, 
contact information, pregnancy status, age, and language. One copy will go to the 
woman (yellow); the other will be saved for the Westat recruiter/helper who will collect 
the forms at the end of the day.  
2. 
Intercept on site. The Westat recruiter/helper will look for women holding a yellow 
referral form and attempt to intercept her at the end of her WIC visit in order to 
introduce the study and screen the woman. Barring that, they will make sure the woman 
gets a study flyer with a toll-free number she can call to learn more about the study. 
Barring that, they will make sure the woman gets a study flyer with a toll-free number 
she can call to learn more about the study.  
3. 
Introduce Study. A Westat recruiter/helper will take the woman to a private space 
(designated for the ITFPS-2 recruitment activity by the site) and introduce the study. 
This will involve providing the woman with a study flyer that explains what 
participation in the study entails, the incentives, and how the mother can play an 
important role in understanding the health of all infants by joining the study. If a 
woman expresses interest in participating in the study but does not have time to go 
through the recruitment process, the recruiter/helper will obtain contact information 
and a Westat telephone recruiter will contact her to introduce the study and determine 
whether she is eligible. 
4. 
Assign to Core or Supplemental Sample. The screener instrument will be 
programmed to assign participants to either the core or supplemental group in an 
alternating pattern. For sampling purposes it is necessary to assign a woman to one of 
these groups before we screen her. (See Sampling Plan, Deliverable 8 for details). In 
sites that have a Westat field recruiter, the recruiter will assign interested new enrollees 
to the core or supplemental sample using a laptop; in sites where a Westat helper has 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-14 
 
introduced the study, the helper will call a Westat number to make contact with a 
Westat telephone recruiter who will assign the woman to the appropriate sample.  
5. 
Administer Screener. Westat recruiters (in-person or telephone) will administer the 
recruitment screener. In sites where the helper calls into the Westat telephone center to 
connect with a telephone recruiter, we will minimize wait time by monitoring call 
volume hourly during peak enrollment periods to ensure that all calls are picked up and 
linked with an interviewer immediately. When needed, we will be prepared to make 
adjustments to both the number of available toll-free staff and responsible interviewers.  
The recruiter will confirm that the woman is eligible (i.e., has not been previously 
enrolled in WIC for her current pregnancy or that the infant is less than 2.5 months). 
Eligible respondents will be asked about their race, ethnicity, trimester of enrollment, 
pre-pregnancy BMI, household composition, and income. Core group participants will 
be retained irrespective of their responses to these questions. Participants assigned to 
the supplemental group may be found ineligible at this stage depending on their 
responses. Only rare population subdomains such as black mothers and infant who 
have no prenatal WIC exposure will be eligible for the supplemental group. Participants 
still eligible will also be asked questions to determine whether they plan to stay in the 
area during the study period, whether they are or will be the caregiver of the WIC 
infant, and their age. In addition, the interviewer will explain what participation 
involves; the number and types of interviews to be completed; and the incentive 
structure.  
6. 
Request Informed Consent and HIPAA Authorization. The Westat recruiters will 
ensure the woman understands all aspects of the study, that her participation is 
confidential and voluntary, and her WIC services cannot be denied if she refuses to 
participate in the ITFPS-2. Consent procedures for mothers under age 18 vary by State, 
and will be determined based on the States identified for sampling. Women recruited in-
person will sign the informed consent and receive a copy of the document for their 
records. Women recruited by telephone will provide verbal consent by agreeing to 
continue with the interview, and will receive a copy of the consent form through the 
mail. Westat recruiters will also request HIPAA authorization from participants assigned 
to the core group to allow access to medical records for enrolled women and their 
infants. Participants recruited in-person will sign the HIPPA form and receive a copy 
for their records; participants recruited by telephone will be sent a HIPPA form to be 
signed and returned in a postage-paid return envelope (see section 4.6.2. or 4-10).  
7. 
Administer Enrollment Interview. Once a woman is determined eligible by the 
eligibility screener and has been recruited, the Westat field recruiter or Westat telephone 
recruiter will administer the enrollment interview which will collect detailed contact 
information (telephone numbers, email address, home address, contact information of 
friends and family members) and health data (due date if pregnant; name and birth date 
of infant if post-natal).  
8. 
Provide Cell Phone if Needed. Since subsequent interviews will be by telephone, if a 
woman does not provide a phone number, a cell phone will be offered for the duration 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-15 
 
of her participation. Westat will mail the phone to the participant prior to the first 
interview (i.e., prenatal, 1 month, or 3 months) with instructions on using it. 
9. 
Provide Incentive and Other materials. Westat will send each participant an 
enrollment package that will include a $50 incentive in the form of a debit card (which 
will be loaded with $20 each time the participant completes an interview); a calendar 
with their interview dates; and measuring guides (for the 24-hour recall) to help them 
with the subsequent interviews. The measuring guides include measuring cups and 
spoons, a household teaspoon and tablespoon, and a ruler.4  
 
4.6.4 
Pre-Test Recruitment Protocol 
We plan to test the recruitment protocol in the September -November 2012 timeframe at three 
different sites located in Los Angeles, Oklahoma, and Baltimore. The sites will be sampled into the 
study and will be chosen based on caseload and geographic location. While we will test the protocol 
at each site, we will not use WIC enrollees. The pretest will help us learn more about WIC sites. In 
particular, we will observe whether WIC site staff are able to accurately identify study eligible 
women and whether the referral form facilitates the entry of the information by WIC staff. We will 
also inspect the physical space available to accommodate enrollments by Westat staff while 
maintaining confidentiality. We will adjust our recruitment protocol as needed after conferring with 
FNS. We will also test prototypes of the data collection and communication tools we plan to use for 
recruitment (e.g., brochures/flyers, computer laptops, and cell phones) within these site 
environments to evaluate their feasibility. Details of our plans for pre-testing were delivered to FNS 
on September 11, 2012. 
 
 
4.7 
Conduct WIC Staff Surveys 
Altarum will instruct staff to complete the WIC Staff Survey during the time period when 
participants are being recruited for the study. All staff persons at each WIC service site who have 
roles providing direct service to WIC participants (e.g., nutritionists, nurses, “competent 
professional authorities”, site supervisors, support/clerical staff, peer counselors and others) will be 
asked to complete a survey. The survey will be confidential and completed on-line or by hard copy 
                                                
4 Of note, the peer Advisory Panel (PAP) purposely recommended not sending participants the USDA Food Model Booklet (FMB) which includes 
pictures of glasses, cups, and bowls, since it might influence a WIC mother’s decision to begin solid foods earlier than appropriate. After discussion 
with S. Murphy of the PAP, FNS agreed that the FMB was not needed to collect data on children between 1-11 months; however, they questioned 
whether this would affect a comparison of the toddler data to the NHANES data (where the FMB is used for this age group). Westat has requested 
the NHANES data to determine the extent the FMB is used to report portion sizes for 12-24 month olds.  

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-16 
 
(if the service site has no internet access). Altarum will introduce the survey to service site staff at 
the in-person visit conducted when site has been recruited. Staff will be informed of the process for 
accessing the survey and of the availability of a Support Desk if they have questions. To maximize 
response rates, Altarum will send periodic notes to the site supervisor or designated point of contact 
to advise them of the number of responses received with a request to remind staff to complete the 
survey. This survey will take about 30 minutes for each staff member to complete. 
 
 
4.8 
Conduct WIC Participant Survey 
The WIC participant sample includes a core and a supplemental sample. As shown in Table 4-1, 
WIC participants in the core sample who are enrolled prenatally will be interviewed up to 11 times 
over approximately a 2-year period. Women enrolled after giving birth will participate in up to 10 
interviews. In the supplemental sample women enrolled prenatally will receive a 1-month interview 
while those enrolled after the baby is born will receive a 3-month interview, and possibly a 1-month 
interview, depending on the age of the infant at enrollment. Both will be interviewed at 3 additional 
time points. Three interviews will be completed during the toddler period.  
 
Table 4-1. 
Interview events for core and supplemental sample 
 
WIC enrollment 
INTERVIEW 
Infant 
Toddler 
Enrollment 
Prenatal 
1 month 
3 months 
5 months 
7 months 
9 months 
11 months 
13 months 
15 months 
18 months 
24 months 
Core Sample – Prenatal 
9 9 9 9 9 9
9
9 9 
9 9
9
Core Sample – Infant <6 wks 
9

9 9 9 9
9
9 9 
9 9
9
Core Sample – infant 6 wks-2.5 mos 



9 9 9
9
9 9 
9 9
9
Supplemental Sample – Prenatal 
9

9


9
 
 
9 
 

9
Supplemental Sample – Infant <6 
wks 
9

9


9
 
 
9
 

9
Supplement Sample – Infant 6 wks-
2.5 mos 



9

9 
 

9
 

9
 
We will conduct the telephone interviews in English and Spanish and participants will be paid a $20 
incentive on completion of each interview. All post-birth interviews will include a 24-hour dietary 
recall using the AMPM. Participants will receive a package of measuring guides to help them report 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-17 
 
their child’s portion sizes during the interview. We will collect replicate intakes on a 10 percent 
subsample of toddlers at 13, 15, 18, and 24 months in order to estimate “usual” intake.5  
 
We will follow the procedures developed by UC Berkeley for the NHLBI Healthy Communities 
Study for obtaining information about foods and drinks consumed by 0-2 year olds who may have 
been in childcare and away from parents on the day they will be reporting their child’s food intake. 
When an interview is scheduled the interviewer will ask the parent/caretaker if their child will be in 
daycare the day before the scheduled interview. If yes, the interviewer will tell the parent/caretaker 
that Westat will send them a note sheet and request that they take it to an adult at the daycare and 
ask the adult to fill in the information (food names and amounts) about what their child consumed 
that day (the day before the scheduled interview). The interviewer will instruct the parent/caretaker 
to pick up the form when they pick up their child at the end of the day and refer to the information 
on the form when they report their child’s intake during the interview the following day. For cases 
when the parent/caretaker cannot obtain the information from the caretaker, we will ask the 
parent/caretaker to provide a report of foods consumed based on their knowledge of what their 
child consumes at daycare. In situations where a parent/caretaker cannot report, we will attempt 
data retrieval with the daycare center. If the daycare cannot provide the information, it will be 
considered missing data. Discussions with the NHANES staff indicate that if the parent/caretaker 
was asked at the 1st 24HR interview about their child’s intake at daycare, they were prepared to 
provide that information at the 2nd interview. Therefore, there is very little missing data in 
NHANES. We expect the same situation in the ITFPS. 
 
At the end of each interview, interviewers will schedule an appointment for the next interview. We 
will remind participants of an upcoming interview through text and email messages, as well as 
telephone calls. Interviewers will make up to nine attempts to complete an interview, spread over 
different days of the week and weekend. Despite these attempts, we anticipate that we will not be 
able to complete every interview with each participant. However, skipping an interview will not 
make a participant ineligible for subsequent interviews. She will still be in the study and our 
interviewers will try to reach her for the next interview for which she is eligible.  
 
Since this is a longitudinal study in which we want the women to remain in the study over a 2-year 
period (and more for women recruited prenatally) we are very sensitive to the need to form a 
                                                
5 We expect the food intakes of infants at 1, 3, 5, 7, 9, and 11 months to be very homogeneous and have no reason to believe this population will be 
different from NHANES. Therefore, we plan to use the data from NHANES 2007-08 & 2008-09 to adjust estimates of usual intakes of infants. We 
estimate the NHANES (2007-8 & 2009-10) represents a sample of about 275 cases 0-5 months and 300 cases 6-12 months old, which is greater than 
a 10 percent subsample of cases in ITFPS. 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-18 
 
relationship with the women and stay in touch with them on a regular basis. To this end, we plan to 
staff study liaisons in this role. These liaisons will make contact via phone and email, with each woman 
after they are enrolled in the study to welcome them and answer any questions. They will make 
reminder calls for upcoming appointments and be available to “find” the woman if our telephone 
interviewers are unsuccessful in contacting her for an interview. They will use social media for 
tracing respondents who we cannot get in touch with to complete an interview during their 
commitment to the study. We will search for respondents on Facebook and send private emails to 
their Facebook email addresses that cannot be viewed by anyone else. In addition, the liaison will 
attempt to contact and schedule interviews with participants who demonstrate “soft refusal” 
tendencies, such as missing their appointments or breaking off in the middle of an interview. The 
liaison will try to address her concerns and hopefully schedule a convenient time to complete the 
interview.  
 
Once a liaison realizes the participant is not communicating with her, she will begin a series of 
tracing steps. First, she will contact the WIC site contact to find out the current contact information 
on her WIC file(). If this does not yield new information, the liaison will attempt to call the contacts 
(generally family and friends) the participant provided during the enrollment interview. If these 
contacts fail to locate the participant, she will attempt to reach her via free on-line searches. Should 
our tracing indicate that a participant has left the country permanently, we will not attempt to 
contact her for subsequent interviews. We will continue to call and complete interviews with 
participants who have dropped out of WIC, enrolled in another WIC site, or moved from the area 
where she was originally sampled to a new area within the United States. 
 
Finally, a second 24HR recall will be collected on a 10 percent subsample of participants from the 
core sample at the 13, 15, 18, and 24 month follow-up interviews to adjust for “usual” intake in 
infants.6 The second interview will be scheduled for completion within 7-10 days of the first 
interview. 
 
 
4.9 
Obtain and Abstract Hospital and Provider Records 
Throughout the data collection period Westat will request and abstract medical records from the 
birth hospital for all core sample enrollees, and child health care provider records for core sample 
enrollees if the infant is no longer in WIC. We will obtain a HIPPA release on completion of the 
                                                
6 Mod 2 memo (3/23/12) states that we will only do 2nd AMPM at 13, 15, 18, and 24 month interviews 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-19 
 
enrollment interview and hospital and provider contact information at either the 1- or 3-month 
interview. We will request medical records from providers at 7, 13, and 24-months to obtain infant 
weight/length and health status for those infants who drop out of WIC. We estimate that 20 percent 
of enrollees in the study may leave WIC over the 3-year data collection period. Records will not be 
requested for those who did not sign a HIPAA form. 
 
 
 
Obtain Records 
The record acquisition process will involve sending a letter of request which will provide pertinent 
information about the ITFPS-2 and specify the type of records requested along with a copy of the 
signed HIPAA Authorization. The requests will be managed and tracked through the study 
tracking/management system. This system documents initial and follow up requests and generates 
reminders at specified times for follow up action. Requests that are unanswered after a certain time 
will be followed with a telephone reminder call and/or additional written requests, and resent if 
necessary.  
 
We understand that individual institutions have established different rules regarding the release of 
medical records and authorizations. For example, the HIPPA is only valid for a specified time 
period, the institution has its own release form, copies of medical records must be paid for, and 
release form must be witnessed by a notary public. In each of these instances we will work with the 
individual institutions to meet their requirements in order to obtain the birth and provider records.  
 
 
 
Abstract Records 
Westat medical abstractors will identify and abstract pertinent data into a study-specific system that 
includes edit checks and verification capability. They will be trained on the specific abstracting 
procedures and how to self-edit their work. Westat supervisory staff will conduct verification on 10-
20 percent of each abstractor’s work to identify discrepancies both in selecting and in abstracting the 
data; any discrepancies will be discussed with the abstractors. If we identify a problem with an 
abstractor’s work, the supervisor will provide additional training. A greater proportion of the 
abstractors work will be reviewed and problem items will be corrected in the database. 
 
 

Data Collection Protocol 4 
 
WIC ITFPS-2 Draft Research & Analysis Plan 
Deliverable 7a 
4-20 
 
4.10 
Obtain and Abstract WIC Administrative Records 
Altarum will obtain administrative records from WIC during the data collection period for key 
milestones in the mother’s and child’s life as follows: 
 
 
Maternal Food Package Information: at enrollment, 1, and 7 months 
 
Child Food Package Information: at enrollment, 1, 7, 13 and 24 months.  
 
Child Weight and Length: requested at 7, 13 and 24 months. The measurement will be 
taken at ages 6, 12, and 24 months. We will obtain records at birth from hospital 
records; 
These data requests have been timed to coincide with WIC clinic visits. The process for obtaining 
these records will vary from State to State. Altarum staff will work with the State and local agencies 
to determine how to best access the data in their WIC information systems, and will document that 
in a summary memo to the sites.  
 
 
4.11 
Obtain Weight and Length Measure Directly on Infants 
Throughout the data collection period Westat will contract with a local home health service to 
obtain weight and length measurements on the core sample of infants who drop out of WIC and do 
not visit a provider for well baby checks. Infant weight will be obtained at 7, 13, and 24 months. The 
Westat study liaison will communicate with the participant to schedule the appointment. A $20 
incentive will be provided once the health care professional obtains the measures. 
 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-1 
 
5.1 
Data Overview 
As discussed in Chapter 4, we will obtain administrative data and key informant data from State 
WIC agencies and from local WIC service sites. We will collect participant data directly from 
participants, from home health services visits and from hospital and provider records. A brief 
description of the data files to be used in the project is presented below and an overview of data 
collection is presented in Table 5-1.  
 
1. 
WIC State Key Informant Interviews: These data will be obtained from selected WIC 
staff in each State agency (determined by the State Agency WIC Director), and will 
contain data on WIC program and policies and activities for each State. Includes data 
collected to clarify information from State documents (plans, policies, descriptive 
information). 
2. 
WIC Administrative Files: These data will be obtained from WIC State or local level 
sources and will contain data on mother and infant or toddler characteristics.  
3. 
WIC Local Key Informant Interviews: These data will be obtained from WIC local 
level sources (probably WIC site coordinators and supervisors) and will contain data 
that clarify local site policies and attitudes related to infant and toddler nutrition 
education and services at the site. It will also be used to create a profile of the local site 
for use in analysis.  
4. 
WIC Local Staff Survey Data: These data will be obtained from local site staff (e.g., 
nutritionists, nurses, paraprofessional “competent professional authorities”, site 
supervisors, support/clerical staff, peer counselors and others) and will contain data on 
local staff characteristics, attitudes, and knowledge about infant and toddler nutrition.  
5. 
Participant Survey Data (Non-AMPM): These data will be obtained from enrolled 
study participants and will include nine different domains (described in section 3.1) 
providing the bulk of analytic data.  
6. 
Participant Survey Data (AMPM Intake): These data will be obtained from enrolled 
study participants and will contain detailed nutritional intake data using the USDA 
Automated Multiple Pass Method (AMPM). 
7. 
Weight & Length (Home Health Service): These files will be obtained from Home 
Health Services providers in cases where the measurements are not available through 
other means. The data will contain weight and length measures. 
Create Data Files 5 

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-2 
 
8. 
Hospital/Provider Data: These files will be obtained from hospitals or providers and 
will contain data on births and hospital stay characteristics. 
In Table 5-1 below, we present an overview of the data files. We have outlined the timing of data 
collection for each data file, the primary owner of the data after data collection, and identifier 
variables in each data file in order to link files with each other. The primary owner of the data is the 
entity responsible for acquiring and processing the data. In Section 5.2, we will discuss the linkages 
and elaborate on identifiers where necessary. 
 
Table 5-1. 
Data files overview 
 
Data 
Source 
Timing of collection 
(after OMB approval) 
Primary 
responsibility 
Identifiers 
WIC State Key 
Informant Survey 
WIC State Level 
Personnel 
0.5-5 months 
Altarum 
State and Local Agency Id 
as available (or created) 
WIC Local Key 
Informant Survey 
Local Agency staff 
& service site staff 
0.5-5 months 
Altarum 
Service site and local 
agency if needed 
WIC Administrative 
Files 
WIC State or local 
Level Personnel 
 
Altarum 
State and Local Agency 
WIC Local Staff 
Survey 
Service site staff 
0.5-5 months 
Altarum 
Service site 
Participant Survey 
(Non-AMPM) 
Enrolled 
Participants 
1-37 months 
Westat 
Case and person 
Participant Survey 
(AMPM) 
Enrolled 
Participants 
1-37 months 
Westat 
Case and person 
Home Health Service 
(Weight/Length) 
Home Health 
Service providers 
16-37 months 
Westat 
Case and person 
Hospital/ Provider 
Files 
Hospitals and 
Providers 
12-37 months 
Westat 
Case and Person 
 
 
5.2 
Data Flow and Creating the Analysis Database 
Figure 5-2 outlines the flow of data from the primary sources to the creation of an analysis database. 
The complete analysis database will be a relational database with multiple SAS data files, each with 
records at varying levels. While the data from the Participant Survey will be at the case and person 
level, the data from higher level entities (such as State and Local Agencies) will be at State or Local 
Agency level. The participant data will be collected up to 11 times over approximately a 2-year  

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-3 
 
Figure 5-2. 
Data flow from sources to analysis database 
 
 
 
period as presented in Section 4. Thus the analysis database will be longitudinal in nature capturing 
multiple entries over time in different data files. All analysis files created will have flags indicating 
rounds of data collection and disposition status when necessary. These files will undergo a 
systematic review process that identifies outliers and tests for internal consistency. 
 
 
5.3 
WIC Key Informant Data Cleaning and Editing 
Altarum will apply standard data handling processes to the qualitative data derived from key 
informant and other non-quantitative exchanges. The task leader will randomly select 20 percent of 
both the State and Local Key Informant Interviews to undergo a thorough review based on the 
recorded interview. Reviewers will listen to each interview in its entirety to ensure that the responses 
recorded into the database are accurate and consistent across the reviewed interviews. The reviewer 
will make changes as needed to the database, and maintain a log of entries to track the questions and 

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-4 
 
responses that posed particular problems for interviewers/recorders. After reviewing the selected 
interviews, the task leader will note whether any individual questions posed a problem for multiple 
respondents, and if so, a more thorough review will be conducted specific to the responses to those 
questions. Once discrepancies in data collection are resolved, Altarum will review responses to 
open-ended questions and develop coding schema (e.g., topics of trainings provided) for analysis. 
NVivo will be used for coding and analysis of the key informant data.  
 
 
5.4 
Administrative Data Cleaning and Editing 
WIC, hospital, and provider administrative data on mother and infant/toddler characteristics will be 
subjected to rigorous data cleaning methods. It is anticipated that much of the data will need to be 
pre-processed either from hard copy (via abstraction), via phone calls with State or local agency 
administrative record sources, or from electronic files (via manipulation and data formatting). The 
issues and controls are well understood by the data management team and procedures to receipt, 
understand, prepare and load quantitative data are already part of the standard operating process.  
 
 
5.5 
WIC Staff Survey Data Cleaning and Editing 
Altarum senior staff assigned to each State will review the survey data with the database manager for 
four potential problems: 
 
1. 
Completion of the Survey. If the information is incomplete, it may be a result of a 
submission error or the respondent not understanding that they should complete all 
sections. If a survey is incomplete, Altarum will contact respondents to be sure they 
intended to submit an incomplete survey, and resolve any issues.  
2. 
Consistency of Responses. Several of the questions are used as screening tools for 
matching respondents with appropriate questions. For example, different questions will 
be asked of those who conduct breastfeeding education than those that only issue food 
packages. We will be sure that all categories of respondent completed the appropriate 
sections that match their role in the WIC site.  
3. 
Errors in Matching State and Local Sites. We will be sure that all data for local WIC 
sites are coded to the appropriate State in order to match State and local features when 
building the database.  

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-5 
 
4. 
Other Coding Inconsistencies. Should we identify any responses that do not make 
sense in terms of consistency or appropriateness, we will attempt to correct these prior 
to entry into the database by contacting respondents to resolve any issues 
Once satisfied that the responses are complete and accurate, the data will be entered into the staff 
survey database for analysis.  
 
 
5.6 
WIC Participant Data (non-AMPM) Cleaning and Editing 
Westat will apply meticulous data cleaning methods to ensure the participant data are of high quality. 
Many of the data cleaning tasks will be built into the computer assisted program. We recognize that 
in longitudinal studies it is possible to collect conflicting information about specific activities that 
will then need to be reconciled. To reduce the likelihood of this happening, we have structured the 
questions asked at each time period in such a way so as to avoid re-asking the same question. For 
example, once the respondent answers that they started/stopped an activity (e.g., breastfeeding), 
further interviews will not re-ask that information.  
 
We will perform post-interview editing to identify anomalies, patterns as well as interviewer and 
programming errors. Automated reports will look at batches of data and based on pre-defined 
checks and output data to be reviewed. Key analytic variables will be compared and validated across 
forms. We will run frequencies and cross-tabulations on key variables which will be reviewed. As 
editing and data review begin and as scenarios are identified and investigated, we expect that the 
standard rules for correcting, deleting, or leaving data as is will develop as decisions are made in 
consultation with the program team and FNS. Once rules are identified, they can be systematically 
applied to future data reviews. Rules will be documented in the data management plan and changes 
will be documented in the data decision log. When appropriate, edit checks supporting the 
application rules will be incorporated into automated edit programs. Training will be provided to 
interviewers should they be the source of error and programming updates or additional edits will be 
coded as appropriate.  
 
 
 
Built-In Edit Checks 
Westat expects to use Blaise to build the WIC participant questionnaire. Blaise is a programming 
language specifically developed for computer assisted interviewing that features a full range of data 
editing capabilities during the interview. These edits will be specified as part of the development 

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-6 
 
process and will result in high-quality data since edit rules will be enforced and corrections made as 
the data are captured. To handle unforeseen situations where edits may not completely cover the 
situation or extreme out-of-range values are encountered, the interviewer may also enter a comment 
or remark at any item. These edits result in minimal missing data (typically the result of “don’t 
know” or “refusal” responses in which the respondent is unable or unwilling to provide a response). 
We will also perform automated, post-collection editing using features internal to Blaise in 
conjunction with Westat’s automated data editing systems and procedures to detect situations that 
may not be covered by the edits incorporated into the instrumentation. Using this approach 
preserves the variable ranges, skip patterns, and edits inherent to the interview while also allowing 
for the addition of edits and re-coding of open-ended responses within the editing process. The 
editing system also maintains a keystroke audit trail for each case. 
 
 
 
Editing Process 
The editing process used for the WIC participant data is divided into three sequential phases. The 
first phase is designed to create manageable editing tasks, review data within the construct of the 
computer-assisted interview, and resolve outstanding data issues found in the field during the actual 
interview. It allows the editor to review the interviewer’s comments, to review all suppressed edits, 
to check for hard edit violations, to review all questions with a response of “don’t know” or 
“refused,” to review all open-ended responses, to determine possible errors in response entry, and to 
identify possible responses that could be coded. The second phase is designed to handle other-
specify coding, coding of verbatim text, expanded ranges for unexpected responses, additional 
consistency edits that may have been too complex to handle during administration of the interview, 
and resolution of interviewer comments. The third phase involves generating SAS reports from the 
edited files which managers will review weekly to identify problems that require a systematic change. 
Edit problems will be addressed using the Blaise editing features or in SAS.  
 
 
5.7 
AMPM Response Data 
Under the guidance of USDA Agricultural Research Service (ARS), Westat has well-established 
procedures for reviewing, consolidating, editing, and coding AMPM dietary recall responses. The 
dietary data processing tasks will take place outside of the Blaise editing process described above. 
This method has been applied to 10 years of National Health and Nutrition Examination Survey 

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-7 
 
(NHANES) collections, as well as other studies using the AMPM. During the data collection field 
period, Westat will receive Blaise data from the field on a daily basis that will be processed at Westat 
in batches using the USDA Post Interview Processing System (PIPS). The PIPS will convert the 
Blaise files to MS Access and apply food codes to about 60 percent of the foods. Once the files have 
been converted, the data will go to Westat’s dietary coding shop, where the contents will be 
confirmed and tracked. Dietary coders will assign codes to foods that were not automatically coded 
during the PIPS process. Trained dietary coders will use standard procedures and established 
guidelines to code the intake data in the USDA SurveyNet coding system through a multiuser 
tracking system that assigns cases and enforces workflow rules to manage the internal editing and 
nutritional coding and third-party validation. Of note, after substantial research by Dr. Harrison and 
our consultant, Dr. Jane Heinig, we propose applying a standard gram weight to each breastfeeding 
occasion using the criteria/cutoff points set by the Gerber Feeding Infants and Toddlers Study 
(FITS).7 The best data available show that the variation in volume and energy intake among 
completely breast-fed babies is substantial, most particularly at 6 months of age, and estimates from 
the DARLING study at UC Davis,8 which utilized test-weighing of infants before and after each 
feeding, indicate that using the FITS cutoffs may substantially under-estimate energy take for fully-
breastfed six-month-old infants.9 However, we estimate that the number of infants fully breast-fed 
in the WIC population is less than 15 percent so will apply a correction factor based on this study 
for this small number of infants, and see whether estimates of nutrient intake cutoffs are different 
with this correction. 
 
In our experience with the AMPM and SurveyNet, there are very few foods that cannot be coded 
using the USDA Food and Nutrient Database for Dietary studies (FNDDS). This is because most 
new foods on the market are derivations of existing foods (e.g., new cereals, juice drinks, power 
bars, etc.). When a new food name cannot be found in the FNDDS, a similar food with the same 
nutrient profile can typically be matched to the new food. Therefore, these foods can be coded using 
existing food codes. This process involves researching the nutrient content of the new food (by 
searching the USDA Survey Database, manufacturer’s websites, websites of other databases) and 
assigning an acceptable food code on the basis of macronutrients (kcal, protein, carbohydrate, fat) 
and selected micronutrients (e.g., carotenes, vitamin C). The match is considered acceptable if the 
nutrients are within 10 percent. We expect that acceptable matches can be determined for almost all 
                                                
7 Butte NF, Fox MK, Briefel RR, Siega-Riz AM, Dwyer JT, Deming DM, Reidy KC. Nutrient intakes of US infants, toddlers, and preschoolers meet 
or exceed dietary reference intakes. J Am Dietetic Assoc.2010; 110: S27-S37. 
8 Dewey K and Lonnerdal B. Milk and nutrient intake of breast-fed infants from 1 to 6 months: relation to growth and fatness. J Pediatr Gastroenterol 
Nutr. 1983; 2: 497-503. 
9 Heinig J. Personal communication, 2012.  

Create Data Files 5 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
5-8 
 
new foods. In instances when an acceptable match cannot be determined, we will assign the closest 
available food code and flag it as needing modification. In the nutrient output file, we will replace 
the nutrients for the flagged food item with the nutrients from USDA’s database or a comparable 
nutrient database. For these modified food codes, we will also review the Food Patterns Equivalents 
assigned to the original food codes and determine if any servings need to be changed.  
 
Additional steps to ensure the quality of the dietary data include significant review and editing 
efforts by senior coding and/or supervisory staff. Senior staff will conduct a 100 percent review of 
coded data, examining the data line-by-line to verify the accuracy of the work. Supervisory staff are 
responsible for the final quality control edits and reconciling intake data that are outside normal 
limits. Reports used to identify outlier values include the portion outlier report, which highlights 
unusually large or small portion sizes.  
 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-1 
 
6.1 
Overview 
We plan to use standard design-based methods for weighting and variance estimation that will lead 
to confidence intervals on means and percentages, and hypothesis tests on contrasts of means and 
percentages. Base weights will be computed as the reciprocals of the probabilities of selection. We 
expect there will be missing data given the large number of planned interviews for each sampled 
member and the high likelihood that some individuals will miss some interviews. If analyses were 
restricted to only complete cases, information from the incomplete cases would be lost and the 
analyses would ignore the possibility that there are systematic differences between the complete 
cases and incomplete cases. We will address this potential nonresponse bias by a combination of 
nonresponse adjustments to the sampling weights and imputation of missing data.  
 
Weighting adjustments can be used to reduce nonresponse bias. However, unless a separate set of 
weights is developed for each subsample being analyzed, weighting adjustments tend not to deliver 
much lower variance than the simple procedure of analyzing only complete cases. In fact, weighting 
adjustments tend to increase variances beyond what one sees in the simple procedure of only 
analyzing complete cases. Although weights are not as transparent as restricting the analysis to 
include only complete cases, they are still fairly easy to understand and are well accepted in the 
survey tradition, at least for cross-sectional surveys or cross-sectional analyses of longitudinal 
surveys.  
 
Imputation is another tool we will use to address missing data and the associated nonresponse bias. 
Imputation has the important advantage that analyses based on imputed datasets can be 
exceptionally clear to a wide set of audiences. However, when imputation is done it is important to 
document clearly which data on microdata sets are imputed, and to explain the uses for which the 
imputed data are more or less well suited.  
 
We begin our discussion with our approach to base weights (Section 6.2). This will be followed by a 
section on our plan for weighting and imputation (Section 6.3). Finally, we close with sections on 
nonresponse bias analysis (Section 6.4) and variance estimation (Section 6.5). 
 
Weighting, Nonresponse Bias Analysis, Missing 
Data Compensation, and Variance Estimation 6 

Weighting, Nonresponse Bias Analysis, Missing
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-2 
 
6.2 
Base weights 
We will develop sampling weights aimed at yielding nearly unbiased estimates of population 
parameters such as the breastfeeding initiation rate. These weights will be based on Horvitz-
Thompson weights, equal to the inverse of the probability of selection. Layered over these will be 
adjustments for nonresponse across the interviews (called “waves” for weighting purposes) of the 
study. One set of weights will be developed for analyses of the core sample by itself. A different set 
of weights will be developed for joint analyses of the core and supplemental sample samples.  
 
 
 
Core Sample 
The Horvitz-Thompson core-sample weight for an infant will be 
 
 
52
22 5
,
22 4
2
ij
ij
i
i
Bijk
ij
ij
ij
ij
C
N
M
E
W
M
D
L
n
 
 
where the first factor adjusts for the fact that the field period contains only 22 of the 52 weeks in a 
year,, 
i
M is the count of new enrollments10 in the i-th stratum according to the PC2010, 
ij
M is the 
count of new enrollments (defined the same way from the same source) in the j-th first-stage 
sampling unit in i-th stratum, the 4 in the denominator adjusts for the fact of sampling four first-
stage sampling units per stratum in the first phase of selection,
ij
E is the number of eligible first-
stage units among the 4 sampled in the i-th stratum, the 2 in the denominator accounts for the fact 
that 2 first-stage units will be selected in the second phase among the 
iE  eligible, 
ij
C is the count of 
clients11 in same first-stage sampling unit according to local reports at the time of first-stage 
sampling unit scouting, 
ij
D is the count of clients in the sampled service site within the j-th first-
stage sampling unit in i-th stratum according to the same local reports, 22 is the length of the field 
period in weeks, 
ij
L  is the length of the window in days, 
ij
N is the number of new enrollees12 
during the window, and 
ijn is the number of clients who are recruited into the evaluation study 
                                                
10  All newly enrolled pregnant women in April of 2010 plus 20 percent of newly enrolled infants. All from the PC2010. 
11 It is not necessary to define clients here as new enrollments although that would be best if possible. Of course, it is important to use whatever was 
used for sampling.  
12 New enrollees here means pregnant women enrolling for the first time during the current pregnancy plus new infant enrollees whose mothers appear 
not to have been on WIC during the gestation of the infant.  

Weighting, Nonresponse Bias Analysis, Missing
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-3 
 
during the window. Here it is important to note that 
ijn  counts those who give informed consent 
and not just those who pass the screening test of not having previously enrolled for WIC during the 
current pregnancy or the pregnancy leading to the birth of the infant being enrolled. 
 
Although this formula appears complex, we hope that the weights will have low variation. Various 
simplifications will come into play in different situations. For a given sampled service site, if the 
entries on the PC2010 identify the service site (rather than a composite site), the service site will 
have been sampled at the first stage of selection and no second stage of service site selection will 
have been needed; in this case we will have
1
ij
ij
D
C
. Even when the second stage of service site 
selection is needed, , as long as the enrollment figures provided for second-stage selection are highly 
accurate, 
,
corr
ij
ij
M C
 should be large and therefore the ratio 
ij
ij
C
M
 should be close to 1. If the 
PC2010 data or the local scouting data turn out to be inaccurate, weights will vary more. On average, 
we expect the weights to be on the order of 550. This is based on an assumption of two million new 
enrollees in a year, 78 percent coverage, and a recruited sample size for the core sample of 2804.  
 
Of course, to the extent that there is bad information at any phase or that there is a shift in site 
operations that reduces the predictive value of past data, the weights will vary. This is a concern 
because highly variable weights reduce the precision of survey estimates, and there is the potential 
for the cases with large outlying weights to have undue influence on estimates. Note that these 
weights will be constant within service site but vary across service sites. If there are isolated 
incidences of sites with weights much larger than the predicted average of 550, we will consider 
trimming the weights to avoid the situation where the results from such an office dominate the 
national estimates on a weighted basis. We are hopeful that this will not be required, but will 
carefully check for the possibility and take appropriate steps if the condition is detected.  
 
 
 
Total Sample 
When analyses use both the core and supplemental samples, a different set of baseweights will be 
required. Let ijk
r
 be the retention rate in the supplemental sample for persons in the sampling 
domain that contains the infant. The baseweight for the infant in the total sample will be
1
1
BTijk
Bijk
ijk
W
W
r
1
1
W
1
Bijk
ijk
B
rij
. This same formula will be used whether the infant was sampled as part of the 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-4 
 
core or as part of the supplemental sample. Note that if the infant is from a rare group that is always 
retained when found (such as children of black mothers), the weight for the infant in the total 
sample will be half the weight it receives when the core sample is analyzed by itself. At the other 
extreme, when an infant belongs to a common group that is never retained when found in the 
supplemental sample (such as children of obese Hispanic mothers), then the baseweight for the 
infant is the same whether the core is analyzed by itself or in combination with the supplemental 
sample. 
 
 
6.3 
Missing Data Compensation 
Given the large number of planned interviews for each sampled mother, it is inevitable that there 
will be missed interviews resulting in complex missing data patterns. We will attempt to mitigate the 
risk of ensuing nonresponse bias by a combination of nonresponse adjustment to the sampling 
weights and imputation. We will prepare a separate set of weights for each wave of data collection. 
The only respondents that will receive a positive weight for a wave will be those who responded to 
the wave and those who missed the wave but returned to the sample after missing no more than two 
consecutive waves. Respondents returning to the sample after one or two missed waves (interviews) 
will be asked some retrospective “catch-up” questions to get the timing of a few critical items where 
transitions are noted such as when nursing mothers stopped nursing, and when cereal was 
introduced into the child’s diet.13 Imputation will be used to fill in scattered item nonresponse within 
completed interviews. It will also be used to fill in data from other sources such as hospital records 
when we have questionnaire data from mothers.  
 
 
 
Weights 
Table 6-1 shows a planned set of weights. In addition to the cross-sectional weight for each wave, 
we will create some longitudinal weights for analyses that require analysis of linked data across 
waves. We note that simple change estimates (as in the percent still breastfeeding) do not require 
linked data. These change estimates will be prepared by forming point estimates for each wave with  
                                                
13 Respondents get the full interview for the month in which they are doing an interview, regardless of missed interviews or which sample they are in 
(core or supplemental). So questions that require reporting a “date” (e.g., cessation of breastfeeding, introduction of formula, or introduction of 
supplemental foods) will be asked at every applicable interview until the mother gives us a date or until the question is no longer part of the 
interviews.  

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-5 
 
Table 6-1. 
Weights to be prepared and delivered 
 
Weight name 
Core only or 
combined? 
Positive for 
respondents  
at which waves? 
Additional notes 
PrenatalWgt 
Core only 
Prenatal 
 
Month1CoreWgt 
Core only 
1-mo 
Only prenatally recruited infants and 
infants recruited postnatally within the 
window for the 1-mo interview  
Month1CombWgt 
Combined 
1-mo 
Only prenatally recruited infants and 
infants recruited postnatally within the 
window for the 1-mo interview 
Month3CoreWgt 
Core only 
3-mo 
 
Month5CoreWgt 
Core only 
5-mo 
 
Month7CoreWgt 
Core only 
7-mo 
 
Month7CombWgt 
Combined 
7-mo 
 
Month9CoreWgt 
Core only 
9-mo 
 
Month11CoreWgt 
Core only 
11-mo 
 
Month13CoreWgt 
Core only 
13-mo 
 
Month13CombWgt 
Combined 
13-mo 
 
Month15CoreWgt 
Core only 
15-mo 
 
Month18CoreWgt 
Core only 
18-mo 
 
Month24CoreWgt 
Core only 
24-mo 
 
Month24CombWgt 
Combined 
24-mo 
 
HazardModelCoreWgt 
Core only 
Prenatal + 1-mo or  
3-mo if postnatally 
recruited 
Good for modeling hazard of weaning & 
introduction of various foods; also good 
for modeling of BF initiation 
HazardModelCombWgt 
Combined 
At least one postnatal 
interview 
Good for modeling introduction of 
various foods. Earliest weight that uses 
entire sample. Larger sample size than 
HazardModelCoreWgt but can’t be used 
in conjunction w/prenatal data. 
InfantCoreLongWgt 
Core only 
Responded every 
wave from birth 
through 13 mo. 
Good for growth curve modeling of 
calories/other variables measured each 
wave. No plans for analysis, but would 
be expected by many users on a RUF. 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-6 
 
Table 6-1. 
Weights to be prepared and delivered (continued) 
 
Weight name 
Core only or 
combined? 
Positive for 
respondents  
at which waves? 
Additional notes 
ToddCoreLongWgt 
Core only 
Responded every 
wave from birth 
forward 
Good for growth curve modeling of 
calories or other variables that are 
measured each wave. No plans to use in 
our analysis, but would be expected by 
many users on a RUF. 
CritWaveLongWgt 
Combined 
1/3, 7, 13, 24 
If prenatally recruited or recruited 
postnatally within the 1-mo interview 
window, responded at mos. 1, 7, 13, and 
24. If postnatally recruited, after the 1-
mo interview window responded at mos. 
3, 7, 13, and 24. Good for growth curve 
modeling with procedures that cannot 
handle missed waves. 
 
the wave-specific cross-sectional weight and then subtracting the two estimates at the macro level to 
get estimates of net change.  
 
The weighting adjustments will be fairly standard. The approach entails giving a zero weight to the 
nonresponding case and redistributing the base weight of the nonrespondent to responding but 
otherwise similar cases. This process is done within nonresponse adjustment “cells.” Nonresponse is 
assumed to be a perfectly random phenomenon within each cell. Once the cells have been defined, 
Westat has standardized software for making these adjustments that we have used very often over 
the last 20 years. The approach we propose to use to form the cells for nonresponse adjustment uses 
a class of procedures known as “doubly robust” adjustments. In contrast to traditional approaches 
for forming nonresponse adjustment cells, these procedures place greater emphasis on the modeling 
of critical outcomes in the development of cells and somewhat reduced emphasis on the modeling 
of nonresponse propensity. In a survey with many outcomes, the challenge is determining the key 
outcomes to use in this modeling exercise. For WIC ITFPS-2, we propose to develop a binary 
indicator at each wave for whether the mother is following recommended feeding practices for the 
age of the infant. We will then model this in terms of data from prior waves to obtain a set of cells 
that vary in maternal conformance to recommended feeding practices. We will then cross these cells 
with the cells defined more traditionally to predict nonresponse propensity. If we use five cells from 
each model, that will give us a total of 25 nonresponse adjustment cells at each wave that vary 
substantially in both propensity to follow recommended feeding practices and propensity for 
nonresponse. Adjusting for nonresponse within these cells will result in doubly robust nonresponse-

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-7 
 
adjusted weights. Nonresponse bias will be reduced for a wide range of statistics with this approach 
but particularly for statistics about suboptimal feeding practices. 
 
The key to effective nonresponse adjustments is the availability of good auxiliary variables to be 
used in the adjustment. The adjustment for those who initially consent but do not respond to the 
initial (prenatal or 1-month) interview is most limited in this regard. We will ask the service sites to 
provide a few key pieces of information about each potentially eligible WIC enrollee for use in 
nonresponse adjustment, including WIC ID; whether the enrollment was prenatal or postnatal; age; 
language; and income. In addition, the recruiter/helper will determine, with the help of the site, 
whether an enrollee refused a study flyer.  
  
Also, we will build models of attrition at each wave based on the data collected to date. Various 
modeling methods could be considered, and these methods have been found to work approximately 
equally well (Folsom and Witt, 1994; Rizzo, Kalton, and Brick, 1996; Judkins, et al 2005); the real 
question is which variables to allow into the modeling and how to deal with missing data in the early 
wave data.  
 
In many surveys, one step (generally the final step) in the sequence of weighting adjustments is to 
calibrate the weights (e.g., using poststratification or raking adjustments) to control totals from 
trusted sources, such as census totals or estimates from administrative record systems or larger 
surveys. In this case, no such trusted source exists, so this calibration step will not be possible. 
 
 
 
Imputation 
Imputation will be used to adjust for item nonresponse, i.e., missing data for particular items among 
those who respond to a given wave. By using imputation to “plug holes” due to item nonresponse, 
we mitigate issues analysts would encounter in trying to analyze data with “swiss cheese” patterns of 
missingness. As with weighting, a carefully designed imputation procedure will reduce bias due to 
nonresponse (in this case, item nonresponse). Further discussion will be needed to identify the 
particular set of items to be imputed but this set should include, at a minimum, variables needed for 
weighting as well as key survey outcomes and covariates.  
 
For imputation, Westat has created new software over the past decade called AutoImpute, which 
uses a cyclical n-partition hot deck (an approach analogous to the Gibbs sampler but using the hot 
deck to generate the imputations). (See Judkins 1997; Judkins et al. 2007; Judkins, Piesse, and 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-8 
 
Krenzke 2008; and Krenzke and Judkins 2008.) This software is designed to facilitate preservation 
of multivariate distributions while also ensuring that imputations maintain skip patterns and adhere 
to constraints. We have used it successfully on about a dozen major surveys, including one with a 
baseline and eight followup interviews. With virtually any imputation procedure, if there are outliers 
and inconsistencies in the data, these can become magnified after imputation. For this reason, it is 
important to carefully edit the data prior to imputation. After imputation, the same analytic edits that 
we ran on the raw data will be run again on the imputed data. As part of this process, will need to 
examine and possibly deal with outliers that could affect imputation. Dealing with outliers might 
involve setting them to missing and imputing for the newly missing data or setting them to 
reasonable boundary values. This type of detail will be worked out in consultation with subject-
matter experts and FNS. 
 
 
6.4 
Nonresponse Bias Analysis 
To the extent that respondents are systematically different from the population as a whole with 
respect to characteristics used in an analysis, the potential for nonresponse bias exists. Statistical 
methods used to compensate for missing data (weighting and imputation) aim to reduce 
nonresponse bias. Since there is generally no way to directly measure the difference in key survey 
characteristics between respondents and the population as a whole, various methods have been 
developed that aim to assess the potential for nonresponse bias.  
 
One approach we will use is to examine bivariate cross tabulations of data from one wave by 
response status at a followup wave to check for evidence of nonresponse bias at followup. Since 
there will be eight waves of followup on the core sample after the first interview for infants recruited 
after birth, and ten waves of followup on the core sample for those required prenatally, there will be 
many possible cross-tabs that could be run. By the 24-month interview, there will be thousands of 
measurements from prior waves that could be used to check for nonresponse bias at the 24-month 
interview. Obviously the scope of these tabulations could quickly become unmanageable. We will 
need to establish a few sentinel variables from early waves to use as benchmarks for first-degree bias 
estimation. We will work with FNS to arrive at a set of key variables to be used for this purpose. 
 
As discussed above, the weighting class adjustments for nonresponse aim to reduce nonresponse 
bias. Thus, while the subgroup response rate analysis described above may be useful in identifying 
the potential for nonresponse bias due to varying response propensities among key subgroups, this 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-9 
 
nonresponse bias may be mitigated through the adjustments for nonresponse. To examine this, we 
will compare unadjusted estimates (i.e., computed using weights that do not include the adjustment 
for nonresponse to the particular wave) to adjusted estimates.  
 
With a longitudinal study such as WIC ITFPS-2, another technique that can be used is to compare 
prior-wave estimates for key statistics for respondents to the given wave to the corresponding prior-
wave estimates computed using the full set of prior-wave respondents. 
 
Another method that could be considered is benchmarking estimates from WIC IFTPS-2 to 
estimates from other sources, provided such external estimates are available. Although 
benchmarking to external estimates is a method commonly included in a repertoire of nonresponse 
bias analysis techniques, it is recognized that this approach does not allow for isolation of bias due 
to nonresponse. Besides nonresponse bias, differences between the survey estimates and external 
estimates might be attributable to temporal differences, differences in survey populations or survey 
measures, or other sources of error such as coverage bias. 
 
 
6.5 
Variance Estimation 
Two broad classes of methods have been developed for computation of standard errors of estimates 
from complex sample surveys: (1) replication methods and (2) Taylor series linearization. The WIC 
ITFPS-2 data files will contain the information necessary for analysts to use either of these 
approaches to compute standard errors. Several software packages are available for the analysis of 
data from complex sample surveys using one or both of these approaches to variance estimation. 
These include WesVar, SUDAAN, the survey procedures in SAS, Stata, and the Survey package in R. 
Users of the RUF from this project will particularly appreciate the ease of use afforded by the 
combination of replicate weights and one of these packages. 
 
 
 
Replication 
Replication methods provide a relatively simple way of estimating variances and have some 
advantages over other variance estimation methods (e.g., linearization approach). The basic idea 
behind the replication approach is to repeatedly select portions of the sample (“replicates”), to 
calculate the estimate of interest for each replicate, and then use the variability among these 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-10 
 
estimates to estimate the variance of the full sample statistics. Different approaches can be used to 
creating these replicates.  
 
For WIC ITFPS-2, 40 replicates will be created, and the replication approach that will be used is a 
modified balanced repeated replication (BRR) method suggested by Fay (Judkins 1990). When 
estimating the variance of ratios of rare subsets, one problem that occasionally arises from standard 
BRR is that one or more replicate estimates will be undefined due to zero denominators. Instead of 
increasing the weights of one half-sample by 100 percent and decreasing the weights of the other 
half-sample to zero as in standard BRR, Fay’s method perturbs the weights by ±100(1-K) percent 
where K is referred to as “Fay’s factor.” The perturbation factor for standard BRR is 100 percent, or 
K=0. For WIC ITFPS-2, K=0.5 will be used.14,15 
 
In order to create the replicates (and also to define the variables needed for Taylor series 
linearization variance estimates), it is necessary to define variance strata and variance units. Each 
stratum defined for the selection of first-stage sampling units will constitute a separate variance 
stratum. The two first-stage units selected each stratum will comprise the first and second variance 
units. For each set of weights defined in Table 6-1, we will develop a set of “replicate” weights in 
addition to the full-sample weights. In order to appropriately reflect the effects of the various stages 
of weighting on the variances of survey estimates (Ernst and Williams, 1987), the procedures used to 
compute the full-sample weights (described in Section 6.2) will be repeated for each of the replicates.  
 
This procedure will slightly overestimate variances since it will not account for the first-stage finite 
population correction (fpc) factor. The first stage fpc factor is the reduction in variance due to the 
fact that the first-stage sampling units will have been selected without replacement rather than with 
replacement. A more complex version of Fay’s method has been developed that captures this fpc 
(see for example Rizzo and Judkins, 2004, which all includes references to earlier related work). 
However, these have not been routinized at Westat and do not appear to be worth the extra 
difficulty in implementation for WIC ITFPS-2 given that most service sites are small and will have 
very small chances of selection, rendering the fpc negligible. 
 
 
                                                
14 Judkins, D. Fay’s method for variance estimation. Journal of Official Statistics, 1990; 6: 223-240. 
15 Rao, J.N.K., and Shao, J. Modified balanced repeated replication for complex survey data. Biometrika, 1999:; 86:403-415. 

Weighting, Nonresponse Bias Analysis, Missing  
Data Compensation, and Variance Estimation 6 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-11 
 
 
Taylor Series Linearization 
Taylor series linearization uses a mathematical approximation to approximate a nonlinear statistic 
with a linear form. The variance of the nonlinear statistic is approximated by the variance of the 
linear function. Software packages that use Taylor series linearization to estimate variances of 
statistics from complex sample surveys require the user to specify design information including 
“stratum” and “cluster” variables. Unlike those based on replication methods, variance estimates 
based on Taylor series linearization do not fully capture the effects of all of the weight adjustments; 
however, in most cases, the differences between Taylor series standard errors and replication-based 
standard errors are not large. The “stratum” and “cluster” variables that allow users to compute 
variance estimates using Taylor series linearization will be provided on the WIC ITFPS-2 files. 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
6-12 
 
This page left intentionaly blank 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-1 
 
We will conduct analyses to answer the 60 research questions articulated in the RFQ as well as 
supplementary questions. Additionally, we will repeat most of the past analyses from the FNS-
sponsored WIC-IFPS-1 and the two Gerber/Nestle Feeding Infants and Toddlers Studies (FITS). 
We will compare current findings to relevant past work and to current objectives and standards. 
 
 
7.1 
Repeating the Analyses of Past Studies 
The most relevant past research is the WIC-IFPS-1 as it focused specifically on the WIC population 
while the other major studies of feeding practices were general population studies. Therefore, in 
repeating past analyses the focus is primarily on the WIC-IFPS-1. We then reviewed the 
Gerber/Nestle FITS studies I and II, the FDA-sponsored IFPS, and the WIC Birth Month Study 
from the perspective of the additional research questions and analyses they contribute beyond those 
addressed by the WIC-ITFPS-1. The FITS are substantially different from the WIC-IFPS-1 and 
focus primarily on nutrient intake, which complements the work done in the WIC-ITFPS-1 and 
provides more detail on nutrient intake. Additionally, although it uses cross-sectional data, the FITS 
include analyses of both infant and toddler feeding practices through 24 months. In contrast, the 
FDA-sponsored IFPS address basically the same research questions as the WIC-IFPS-1 but cover 
the general population. Additionally, these studies collected detailed information on topics that are 
only tangentially relevant to WIC objectives such as food safety practices, infant and mother sleep 
patterns, and infant food related-health problems. To include these topics in the data collection 
would increase the response burden beyond acceptable levels. Given the overlap in research 
question and the tangential nature of some of their additional research, we will not separately 
replicate the analyses from the FDA IFPS. Similarly, the WIC Birth Month Study also heavily 
overlaps with many of the topics addressed in WIC IFPS-1 but addresses them in more detail as the 
study only covers nutritional issues during the first month of life. We repeat analyses from the Birth 
Month Study to the extent that our data collection supports. Finally, because the schedule of 
interviews includes both infant and toddler data collection, some of the WIC-IFPS-1 analyses will be 
repeated using different time points. Table 7-1 provides a summary of the analyses we intend to 
repeat and those we do not intend to repeat. Additionally, in Appendix A, we provide a listing of all 
Analysis 7 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-2 
 
the tables and figures in the final WIC-IFPS-1 report noting whether we will repeat this work or no. 
In the cases in which we will not be repeating the work we provide an explanation for this decision. 
 
Table 7-1. 
Summary of analyses to be repeated from previous studies 
 
Primary topics 
Summary analyses repeated 
Analyses not repeated 
WIC-IFPS-1 
 Breastfeeding 
patterns, intensity, 
and duration 
 Reasons for 
stopping 
breastfeeding 
 Transitional and 
complementary 
feeding 
 Timing of these 
decisions 
 Supplemental foods 
 Tabulations and comparisons (Chi2 tests) by 
subgroups (e.g., percentage initiating 
breastfeeding by socio-demographics) 
 Frequencies over time (e.g., percentage still 
breastfeeding by age of infant) 
 Factor analysis (e.g., dimensions for 
breastfeeding attitudes and knowledge)but 
items will be updated 
 Logistic regressions for probability of an event 
(e.g., initiating breastfeeding) 
 Survival analyses for time until an event (e.g., 
time until cereals are introduced) 
 Interim models that only use a 
subset of the covariates 
 OLS regressions of 
breastfeeding frequency (e.g., 
counts of number of breastfeed 
at month1) 
 
FITS I and II 
Nutrient intake 
 Food and nutrient intake estimates 
 Frequencies over time(e.g., percentage 
consuming vegetables by age of infant) 
 One-day nutrient intake distributions (e.g., 
overall intake and prevalence of inadequate 
and excess) 
 Tabulations of developmental 
milestones 
FDA 
As the FDA study significantly overlaps with the WIC-IFPS-1 and FITS, no additional analyses will be repeated 
from the FDA study 
 
 
7.2 
Key Analytical Variables 
 
Outcomes and Key Feeding Decisions 
To answer the research questions and update past analyses, we will assess feeding practice decisions, 
child nutrient and food intake, and weight outcomes. As the variety of foods infants consume is very 
limited in the initial months of a child’s life, the feeding practices the caregiver employ are key to 
nutrient intake. In contrast, once the child is eating a variety of foods, direct food intake measures 
become the most important measures of dietary quality. The main feeding practice decisions and 
outcomes are listed below. All variables will be examined by frequencies and how they vary by key  
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-3 
 
socio-demographics, however, only those that are not italicized will be used as outcomes in the 
causal model estimations.  
 
 
Breastfeeding Decisions. Intent to breastfeed, initiation of breastfeeding, first hospital 
feeding, breastfeeding at hospital discharge  
 
For Those Who Breastfeed. Use of breast pump, time until formula supplementation, 
time until breastfeeding cessation 
 
Other Infant Feeding Practices. Number of feedings per day, time until cereal, time until 
baby foods (by type), duration of bottle use, timing of feeding transition 
 
Nutrient Intake and Weight Outcomes. Foods eaten by type, calorie intake per kilogram of 
body weight, usual nutrient intakes relative to Estimated Requirements (EARs) (where these exist and 
Adequate Intakes (AIs) otherwise), nutrient densities, nutrient intakes relative to UL (where these 
exist), weight-for-length, weight/length gain (0-6 months), weight/length gain (6-12 months). 
To translate the dietary data obtained from our interviews into measures of usual nutrient intake, we 
will use the NCI method16 developed by researchers at the NCI, the USDA, and elsewhere. The 
NCI method is a unified framework for estimation of usual intake of nutrients and foods. It models 
usual intake as the product of the probability of consumption on a given day and the average 
amount consumed, which is conditional on having consumed a positive amount. It takes into 
account zero-consumption days and reported consumption-day amounts that are positively skewed, 
and distinguishes between within-person and between-person variation in consumption. It also 
allows for efficient estimation of usual intake for subgroups. Instead of stratifying the sample by 
subpopulation and estimating usual intake separately for each subgroup, covariates defining 
subgroups are included in the NCI model, such that (difficult to estimate) variance components may 
be estimated simultaneously for the full sample, and only covariate values differ. For subgroups of 
respondents comprising a relatively small proportion of the full sample, the efficiency gains from 
this capability are likely to be relatively substantial. 
 
 
 
Comparison Groups and Covariates 
We will assess participants’ outcomes and decisions by subgroups to identify subpopulation 
differences. Using the conceptual causality models and the past research as a guide, we will model 
these outcomes and decisions as a function of a set of covariates that are possibly predictive of the 
outcome (or decision) under study. The core analytical comparison groups will be similar to the 
                                                
16 http://riskfactor.cancer.gov/diet/usualintakes/details.html 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-4 
 
socio-demographic categories that were used in the past studies and will include race, ethnicity, 
mother’s age, mother’s education, mother born in the United States, father living in the home, 
poverty level, and infant’s birth order. Our comprehensive data collection will allow us to explore 
the impact of a few additional socio-demographic variables such as household food security and 
acculturation on feeding practices and nutrition outcomes. 
 
As we showed in the conceptual models, in addition to these socio-demographic variables, data on 
maternal and family health, the mother’s attitudes, beliefs and knowledge, the mother’s experience 
and receipt of advice, the mother’s hospital experience, the mother’s lifestyle choices, and toddler 
feeding practices, will serve as categories of covariates in the analyses. We expect that a large number 
of the potential individual variables within these covariate groups will be correlated as on many 
topics we are asking specific information about attitudes and behaviors. Therefore, many of the 
interview questions will be highly related. For example, to obtain information about the mother’s 
attitudes, beliefs and knowledge regarding breastfeeding will require asking a battery of questions, 
with each question revealing a specific viewpoint. It is likely that women who are pro-breastfeeding 
answer the set of questions one way while those who are not answer differently which would result 
in highly correlated responses among participants. Including highly correlated variables in a 
regression model can make interpreting results difficult and lead to multicollinearity. We will explore 
using principal component analysis to transform sets of potentially correlated variables into a set of 
uncorrelated composite measures. We will explore using this data reduction technique to summarize 
the responses to questions regarding: (1) maternal attitudes, belief, and knowledge about 
breastfeeding, (2) hospital experience and (3) toddler feeding practices. Because the development of 
meaningful composite measures is dependent on the correlation between items, we are not able to 
guarantee, in advance, that this technique will yield useful composites in all cases.  
 
 
 
WIC Program Variables 
A key variable of interest in assessing infant feeding practices is the mother’s experience with the 
WIC program. There is variation in participants’ experiences with WIC because there are differences 
in: (1) the services and education provided at the local clinic, (2) the State polices and supplies 
provided (3) the training and attitudes of the local WIC clinic staff, and (4) the time spent in the 
program. Westat proposes to improve the measure of participants’ WIC program experience and 
capture this variation by developing a series of composite measures. We propose five composite  
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-5 
 
measures for capturing program variation and identify the expected contributing factors to each 
measure as follows:  
 
 
Variation in education offered measured by the number of education contacts 
offered, educational topics offered, delivery method, training of the staff, knowledge 
and attitudes of the staff. (In addition to this program-offering composite, we will have 
information on the educational programs the individual attended which can be used as a 
separate covariate). 
 
Variation in breastfeeding peer counseling measured by the ratio of counselors to 
participants, education and training of the staff, and knowledge and attitudes of the 
staff; and 
 
Variation in the provision and support for breast pumps measured by types of 
pumps available, policies on issuance, support education provided, and knowledge and 
attitudes of the staff regarding pumps 
 
Variation in the food packages measured by package choice substitutions available 
based on the State plan and attitudes of the staff regarding the importance of the food 
packages, substitutes, and alternative diets. 
 
Variation in time in WIC measured by number of days of current participation, 
number of years of participation associated with previous children, joined pre-natal or 
post-partum. 
We will use these composite variables to capture the cross-sectional variation in WIC program 
experience, or “dosage” of WIC exposure, among program participants.17 
 
It should be noted that ultimately the variation in service delivery we observe between sites will 
determine which factors to include in our composite measures as well as whether the final measures 
are effective in capturing meaningful program variation that can be related to policies. Therefore, to 
some extent this work will be exploratory and we will assess alternative composites. For example, if 
we find the quality of sites’ educational programs vary by phase we will consider having separate 
composites for newborn feeding, infant feeding transition, and toddler feeding. In contrast, if sites 
that deliver effective newborn feeding education, almost always also deliver strong infant feeding 
transition and toddler feeding programs, a single education composite will suffice. 
                                                
17 The WIC program variables will be composite measures. A composite measure is a combined metric that incorporates multiple individual measures 
to provide a single score. It is used as a way to measure concepts that are too complex to be measured simply with one item. Composite measures are 
also a data reduction technique used to avoid having many highly correlated variables in the same analyses which creates statistical challenges. The 
five WIC program variables will be composite measures of the component variables listed in the Research Plan and are intended to capture different 
aspects of how the program is being delivered and experienced. For each of the five composite measures, we will develop weights for the component 
variables and combine them into a single score (index variable). A simple approach for doing this is to take a straight average of all the component 
variables but this approach would not address the differing importance of the component items or their correlation with each other. We propose to 
use factor analysis (a statistical technique) to determine the relative weights to use in the creating the composite measure. 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-6 
 
 
As we discuss in the study sampling plan, we will develop a typology and collect information from 
the States regarding WIC program features that will be used to stratify sites for sampling. Once the 
sample of service sites is selected, we will collect more detailed information from these sites 
regarding their WIC program features and operations through a series of key informant interviews. 
Together, these data will capture both State and local policies and offerings and will allow us to 
develop more refined categorical measures of the WIC program that reflect the variation in supplies, 
services, and educational offerings among service sites. Finally, through the staff survey, we will 
collect information on staff training and attitudes.  
 
 
7.3 
Main Types of Analyses 
We will conduct both descriptive and causal analyses to answer the 60 research questions and update 
the analyses from past studies of the WIC program. Many of the research questions can be answered 
by descriptive analyses that tabulate the responses to specific questions (e.g., what are the mother’s 
reported breastfeeding problems?) or characterize the attributes and behaviors of different 
subpopulations (e.g., what are the distributions of caregiver and participants health-related 
characteristics by race and ethnicity of the mother?). A small subset of the research questions focus 
on understanding the underlying population and program factors that drive nutritional outcomes 
and decisions. Therefore, we will conduct basically four types of analyses as follows: 
 
 
Descriptive analyses 
– 
Single month cross-sectional snap shots 
– 
Repeated monthly (or key month) cross-sectional snap shots  
– 
Longitudinal calculations (i.e. we read across several interview months to calculate 
the measure of interest such as the average age children start cereal) 
 
Causal analyses 
– 
Model estimations 
We will use descriptive statistics (counts, proportions, means, medians, distributions (percentiles), 
means, medians,) and cross-tabulations) to examine key decisions and conditional outcomes by 
subgroups (e.g., how do the feeding practices of infants and children who continue in WIC compare 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-7 
 
to those who leave the program18 or have non-continuous participation?). For questions like these, 
the differences will be examined between subgroups by comparing descriptive statistics across 
subgroups such as the proportions that engage in given feeding practices. This will determine if the 
subgroup statistics are different using the appropriate statistical significance tests (e.g., Chi2 test for 
proportions and t-test for means that are adjusted for the cluster sample design). The advantage of 
descriptive cross tabulations is they are straightforward but they will not capture the impact multiple 
factors may be having on a decision or outcome and therefore may overstate the importance of the 
subgroup variables.  
 
For the subset of the research questions that focus on identifying the causal relationships that drive 
the outcomes and decisions observed, we will use multivariate analyses such as regression analysis to 
explore how choices and characteristics impact feeding practice decisions and nutrition outcomes 
while holding other contributing factors constant. We will use Ordinary Least Squares (OLS) 
regression, logistic and multinomial logistic regression, survival analysis, quantile regression, and 
growth models to answer these questions. We will apply OLS regression models to explore how 
continuous dependent variables are, on average, impacted by background characteristics, 
experiences, and decisions. We will use Logistic (and multinomial) regression to model how 
dichotomous (and categorical) decisions and outcomes (e.g., the decision to breastfeed) are impacted 
by background characteristics, experiences, and past decisions. Similarly, we will use survival analyses 
to model how background characteristics, experiences, and past decisions affect time duration until 
an event (e.g., number of day until breastfeeding cessation). Finally, for investigating weight 
outcomes, we will initially explore the relationships between predictors and outcome using OLS 
regression but then will use quantile regression to estimate impact that the explanatory variables 
have on the dependent variable quantiles (we propose using quintiles but will also explore other 
slices of the distribution). This will provide insight into how the explanatory variables affect each 
weight/length quintile (top 20 percent of the distribution, etc.) rather than the mean level as OLS 
regression does. Additionally, we will use growth models to estimate the impact that covariates have 
on the weigh/length growth trajectory. 
 
 
                                                
18 We will continue to interview women who leave the WIC program with the understanding that there may be a drop off in their interview 
cooperation rate. 
We will use Logistic (and multinomial) regression to model how 
dichotomous (and categorical) decisions and outcomes (e.g., the decision to breastfeed) are impacted
by background characteristics, experiences, and past decisions.

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-8 
 
7.4 
Data Challenges 
Over a two year data collection period, it is highly likely that participants will miss some of the 
interviews. First, we will minimize the number of missing variables by repeating questions across 
interviews and recording the date of change of critical behaviors. For example, if a woman stops 
breastfeeding in month 5 and misses the month 5 interview, we will capture when she stopped in the 
7-month interview. Second, as we discuss in our sampling plan, we use a combination of imputation 
for key variables and weight to address issues of missing data.  
 
In addition to missing specific interviews, we are likely to have some individuals for which the data 
are censored (all their data are missing either prior to or after a specific date). This is likely to occur 
for several reasons including (1) individuals drop out of the study, (2) the study timeline is not long 
enough to observe the variable of interest for all participants, and (3) mothers enter the study at 
different times during their pregnancy or postpartum. Left censoring will be an issue for women 
who join WIC after their babies are born and we will address these cases by separately examining 
relevant subsamples based on time period they entered the study. In cases of right censoring, as long 
as the censoring is independent—unrelated to the subsequent risk of the event— within a covariate 
group (e.g. women who return to work), the hazard function (the failure rate in survival analyses) 
can be estimated. For example, right hand censoring may occur because women drop out of the 
study and we do not observe a key outcome such as the when they stopped breastfeeding. In these 
cases, we will only know that they breastfed up to a point in time. As long as there are no 
unobservable factors that systematically affect who leave the study, we can still include the censored 
data in estimating the hazard function without bias. 
 
 
7.5 
Specific Proposed Analyses 
Table 7-2 provides a summary of the analyses we will undertake that directly address the 60 research 
questions and repeat the past work of IFPS-1. The table is organized by topic area and documents 
how we will report the findings in table and figure shells, by title. To keep the interviews under 30 
minutes and balance the length across interviews, we ask many questions only at select interviews. 
Additionally, depending on when women join WIC, their baseline interview can occur within the 
prenatal, month 1 or month 3 interview. In cases where there is a series of interview months listed 
(e.g. Month 1, 3), we will calculate the measure for each of those months. In contrast, when we refer 
to cumulative data (e.g., Cumulative; Months 1, 3) we intend on reading across those months of data 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-9 
 
to calculate the measure of interest. For example, to determine the percentage of women who 
initiate breastfeeding we need to read both the month 1 and 3 interviews as the first interview may 
occur at month 3 for women who enter the study postpartum. If the analysis uses data sources other 
than the WIC participant interviews, we note this in the parenthesis as well. In the second column, 
we provide the source for the table which may be IFPS-1 or FITS or it may be new. Finally, in the 
last column we note whether we will use the both the core and supplemental sample, just the core 
sample, and other data sources. To the extent possible we will use both the core and supplemental 
samples together. There are some cases in which the data are not available from the supplemental 
sample (e.g. they do not participate in the prenatal interview) as it is not collected as frequently.  
 
For the majority of proposed tabulations in Table 7-2, the percentage of participants following a 
given feeding practice or who have a certain attribute or experience will be compared among 
subgroups. We will use a Chi2 test adjusted for the cluster sample design to determine if the 
proportions are statistically different between subgroups. In a few cases, such as the comparison of 
the average number of breastfeeds per day by socio- or pair wise comparisons and F-tests to 
determine if there are no differences across all the subgroups.  
 
Table 7-2. 
Summary of analyses to be conducted 
 
Table/Figure (interview months) 
Source 
Sample 
Study design and sample 
Table: Overall study participation counts and rates (Baseline) 
IFPS-1 p20 
Both 
Table: Counts and percent of respondents by sample type and interview 
month (Baseline) 
IFPS-1 p21 
Both 
Table: Percentage distribution of socio-demographic characteristics by 
maternal/caregiver race and ethnicity (Baseline) 
IFPS-1 p25 
Both 
Table: Percentage distribution of reported health-related characteristics by 
maternal race and ethnicity of the mother (Month 1) 
IFPS-1 p26 
Both 
Prenatal Views 
Table: Mother’s intention to breastfeed by socio-demographics (Prenatal) 
New 
Core 
Table : Items that constitute the perceived benefits of breastfeeding and 
perceived barriers to breastfeeding scales (factor analysis) (Prenatal) 
IFPS-1 p71 
Core 
Table: Percentage of mothers agreeing with statements about perceived benefits 
of breastfeeding by breastfeeding decision (Prenatal) 
IFPS-1 p73 
Core 
Table: Percentage of mothers agreeing with statements about perceived barriers 
to breastfeeding by breastfeeding decision (Prenatal) 
IFPS-1 p74 
Core 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-10 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Mother/Caregiver’s WIC Experience 
Table: Percentage of mothers/caregivers who have previously participated in WIC 
by the length of participation (Baseline) 
New 
Both 
Table: For the current child, percentage distribution of when the mother/caregiver 
joined WIC by infant age (Baseline, Screener)) 
New 
Both 
Table: Percentages of mothers reporting receipt of information about various 
aspects of infant feeding from WIC (Month 1) 
IFPS-1 p28 
Both 
Table: Percentage distribution of the mothers’ views of the relative importance of 
WIC food and educational benefits (Months 3, 13, 24) 
New  
Both 
Table: Percentage of mothers reporting they changed specific feeding practices 
based on something they learned at WIC (Months 3, 13, 24) 
New 
Both 
Table: Top eight most important change mothers made based on education you 
received from WIC (Months 3, 13, 24) 
New 
Both 
Table: Percentages of mothers reporting receipt of information about infant 
feeding from other professional sources (Month 1) 
New 
Both 
 
Table: Percentage of WIC participants using each type of WIC service (accounting 
for service availability) (Prenatal, Months 3, 7) 
New 
Both 
Table: Percentage of caregivers/infants by type of food package (Months 1, 3, 7) 
New 
Admin. 
data 
Knowledge, Attitudes, and Sources of Information 
Table: Percentage of mothers having certain knowledge and attitudes about 
nutrition and behavior (Month13) 
New 
Both 
Table: Percentage distribution of mother’s perception of physician’s views about 
breastfeeding preemies (Month 1) 
New 
Both 
Table: Percentage distribution of mother’s perception of physician’s views about 
breastfeeding (Month 1) 
New 
Both 
Table: Percentage of mothers/caregivers reporting challenges getting nutrition 
information by source(Months 5, 15) 
New 
Core 
Table: Percentage distribution of mothers/caregivers sources of nutrition 
information (Months 5, 15) 
New  
Core 
Table: Percentage distribution of mothers/caregivers most helpful sources of 
nutrition information (Months 5, 15) 
New 
Core 
Table Triggers for seeking nutrition information (Months 5, 15) 
New 
Core 
Table: Percentage of WIC staff having certain knowledge and attitudes about 
infant and toddler nutrition (Staff survey) 
New 
Staff 
survey 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-11 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Knowledge, Attitudes, and Sources of Information (continued) 
Table: Percentage of WIC staff with certain training and certifications (Staff 
survey) 
New 
Staff 
survey 
Table: Percentage who Reported Information from Various Sources to be 
"Important or Very Important" in Deciding How to Feed Their Infant (Month 1) 
WBM, p72 
Both 
Breastfeeding Decisions 
Table: Breastfeeding initiation rates by selected socio-demographic and health-
related characteristics (Cumulative; Months 1,3) 
IFPS-1 p53 
Both 
Figure: Breastfeeding initiation rates, by race and ethnicity of the mother 
(Cumulative; Months 1, 3) 
IFPS-1 p54 
Both 
Table: Breastfeeding initiation rates by intention rates (Cross of prenatal and 
month 1) 
New  
Core 
Breastfeeding Initiation, Overall and by Mother's Food Package (Cumulative; 
Months 1, 3) 
WBM, p112 
Both 
Table: Percentage of WIC mothers by previous feeding practice experience for 
siblings (Baseline) 
New 
Both 
Table: Average longest duration of previous breastfeeding experience (Baseline) 
New 
Both 
Table (Model): Estimates of the relative odds estimated by logistic regression 
model of breastfeeding initiation (Cumulative; Months 1, 3)  
IFPS-1 p58 
Both 
Figure (Model): Relative odds of initiating breastfeeding for WIC mothers who 
received breastfeeding information and advice from different sources 
(Cumulative; Months 1, 3) 
IFPS-1 p63 
Both 
Hospital Practices and Neonatal Circumstances  
Table: Percentage of multiple births and type of delivery (Month 1) 
New 
Both 
Table: Percentage distribution of infants’ health characteristics (Month 1) 
New  
Both 
Figure: Number of days of hospital stay for WIC mothers and infants (Month 1) 
IFPS-1 p109 
Both 
Figure: Percentage of WIC infants who stayed in the nursery overnight (Month 1) 
IFPS-1 p109 
Both 
Table: Percentage of mothers encouraged to breastfeed by family, WIC staff, or 
provider (Month 1) 
New 
Both 
Table: The first feeding received by WIC infants in the hospital (Month 1) 
IFPS-1 p110 
Both 
Table: Percentage of mothers who initiate breastfeeding in the hospital by time 
after birth (Month 1) 
New 
Both 
Figure: The first feeding of WIC infants in the hospital, by race and ethnicity of the 
mother (Month 1) 
IFPS-1 p111 
Both 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-12 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Hospital Practices and Neonatal Circumstances (continued) 
Table: Percentages of mothers reporting nursing problems while in the hospital 
(Month 1) 
IFPS-1 p113 
Both 
Table: Percentage of infants who received something other than human milk in 
the hospital by product, day and frequency (Month 1) 
New 
Core  
Table: Percentage of WIC mothers who reported receiving various services from 
the hospital (infant in room, feeding on demand, referral for breastfeeding 
support, etc.) (Month 1) 
New 
Both 
Figure: Percentage of WIC mothers who did not receive help from the hospital 
staff among those who had common nursing problems (Month 1) 
IFPS-1 p114 
Both 
Figure: Percentage of WIC mothers who reported receiving various items in their 
gift packages from the hospital (Month 1) 
IFPS-1 p115 
Both 
Table: Percentage of type of feeding at hospital discharge by type of first feeding 
(Month 1) 
IFPS-1 p116 
Both 
Table: (Model) Relative odds of formula feeding at hospital discharge for WIC 
mothers who breastfeed at the first feeding (Month 1) 
IFPS-1 p118 
Both 
Table:(Model) Relative odds of breastfeeding at hospital discharge for WIC 
mothers who formula feed at the first feeding (Month 1) 
IFPS-1 p120 
Both 
Table:(Model) Estimates of relative odds of breastfeeding at hospital discharge 
for WIC mothers (Month 1) 
New 
Both 
Formula Supplementation 
Figure: Percentages of only breastfeeding, combined breast-and formula feeding, 
and only formula-feeding WIC mothers at each month of interview (Months 1-13) 
IFPS-1 p88 
Both 
Table: Transitions of Mother’s Food Package Issued by Age of Infant (Months 1, 3) 
WBM, p100 
Core 
Table: Percentage distribution of the perceived impact of food package choice on 
the breastfeeding decision (Months 3, 7) 
New  
Both 
Table: Percentage distribution of the infants by initial diets at the time of each 
interview month; by selected socio-demographic characteristics (Months 1, 3)  
IFPS-1 p90 
Both 
Table: Usual number of formula or combination feedings, by selected maternal 
socio-demographic characteristics(Months 1, 3, 5)  
New 
Both 
Table: Usual number of solid food feedings , by selected maternal socio-
demographic characteristics (Months 1, 3, 5) 
New 
Both 
Figure:: Percentages of breastfeeding WIC mothers, by type of breastfeeding 
practice at each month of interview (Months 1-9) 
IFPS-1 p92 
Both 
Figure: Percentage of breastfeeding WIC mothers who have not yet initiated 
formula, by the age of the infant (Months 1-9)  
IFPS-1 p94 
Both 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-13 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Formula Supplementation (continued) 
Table: Breastfeeding frequency, intensity, and duration by initial breastfeeding 
status(breastfeed only or with formula) (Months 1, 3, 5, 7 ) 
New 
Both 
Table: Intensity of Breastfeeding, Overall (Month 1) 
WBM, p126 
Both 
Table; Intensity of Breastfeeding, by Mother's Food Package (Month 1) 
WBM, p127 
Both 
Table: Median age in weeks of the infant at the time when formula 
supplementation is initiated, by selected socio-demographic characteristics and 
previous breastfeeding experience (Cumulative; Months 1-13) 
IFPS-1 p94 
Both 
Table: (Model) Estimates of the relative risk estimated by the multivariate models 
of rates of formula supplementation (survival analysis) (Months 1-13) 
IFPS-1 p96 
Both 
Breastfeeding and Formula Feeding Practices 
Table: Breastfeeding schedules of WIC mothers over the first five months of their 
infants’ first year (Months 1, 3, 5 )  
IFPS-1 p128 
Both 
Table: Breastfeeding schedules of WIC mothers over the first 13 months of their 
infants’ first year by mother’s work status and child care status (Months 1-13)  
New 
Both 
Figure: Percentage of WIC mothers who breast feed on a set schedule, when the 
infant cries or seems hungry, and on a mixed schedule (Months 3-13) 
IFPS-1 p130 
Both 
Table: Usual number of daily breastfeeds, by selected maternal socio-
demographic characteristics (Months 1, 3, 5) 
IFPS-1 p131 
Both 
Table: Mean and standard deviation in the number of breastfeeds and intensity 
(% of feedings that are breast milk) per day by month (Months 1-7) 
New 
Both 
Table: Percentage of caregivers who respond to different infant cues with 
appropriate understanding (Month 3) 
New 
Both 
Table: Average amount of expressed milk for breasting mothers at 1 month in 
past 24 hours (Month 1) 
New 
Both 
Table: Percentage distribution of what was done with the expressed milk  
(Month 1) 
New 
Both 
Table: Percentage of WIC mothers who report expressing milk during the past 
week, by selected maternal socio-demographics (Months 1-7) 
IFPS-1 p132 
Both 
Table: Percentage distribution of reason for pumping (Cumulative; Months 1-7) 
New  
Both 
Figure: Percentage of breastfeeding WIC mothers expressing milk, using electric 
breast pumps, using manual breast pumps, and expressing milk by hand 
(Cumulative; Months 1-7) 
IFPS-1 p133 
Both 
Table: Percentage of breastfeeding WIC mothers expressing milk, using electric 
breast pumps, using manual breast pumps, and expressing milk by hand by work 
status and receipt of WIC support services (Months 1-7) 
New 
Both 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-14 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Breastfeeding and Formula Feeding Practices (continued) 
Table: The average number of times a day women pump or express among those 
doing this (Months 1-13) 
New 
Both 
Table: Percentage distribution of pumping/expressing milk by time of day and 
storage practices (Months 1-13) 
New 
Both 
Table: Percentage distribution of sources for pumps (Cumulative; Months 1, 3) 
New 
Both 
Table: Percentage distribution of reasons for using formula by infants age  
(Months 1-13) 
New  
Both 
Table: Percentage distribution of formula-feeding WIC mothers by brand name of 
formula  
IFPS-1 p145 
Both 
Table: Percentage distribution of formula types (Cumulative; Months 1-13) 
New 
Both 
Table: Percentage distribution of formula source (Cumulative;  
Months 1-13) 
New 
Both 
Table: Percentage distribution of formula source for women choosing the 
breastfeeding package (Cumulative; Months 1-13) 
New 
Both 
Table: Percentage of caregivers who deviate from formula dilution directions by 
type of deviation, mixed formula with unboiled water, and kept mixed formula for 
more than 24 hours (Cumulative; Months 3,7,11) 
New 
Both 
Table: Percentage of caregivers receiving doctor or nutritionist dilution guidance 
that deviate from recommendations by type of deviation (Cumulative; Months 1-
13) 
New 
Both 
Figure: Percentage of mothers who report adding other foods or liquids in the 
bottle with the formula at Month 3(Month 3) 
IFPS-1 p142 
Both 
Figure: Percentage of mothers who report adding other foods in the bottle with 
formula at Month 1 among those who think that the amount of formula given by  
WIC is more than enough, the right amount, or not enough(Month 1) 
IFPS-1 p143 
Both 
Table: Percentage of children using pacifiers and timing of introduction (Month 3) 
New 
Both 
Table: Percentage distribution of pacifier use by reason (Month 3) 
New 
Both 
Breastfeeding Problems 
Table: Reported breastfeeding problems by WIC mothers at the time of the month 
1, month 3 and month 5 interviews (list of problems; including environmental) 
(Months 1, 3, 5) 
IFPS-1 p153 
Both 
Figure: Percentage of breastfeeding WIC mothers who report experiencing 
breastfeeding problems in Months 1,3, and 5 (main types of problems)  
(Months 1, 3, 5) 
IFPS-1 p154 
Both 
Table: Percentage of mothers reporting breastfeeding problems in first 5 months 
by type of problem and socio demographics (Cumulative; Months 1, 3, 5) 
New 
Both 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-15 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Breastfeeding Problems (continued) 
Table: Percentage of mothers reporting breastfeeding problems who received 
help by source of help (Cumulative; Months 1, 3, 5) 
New 
Both 
Table: Percentage distribution of resolutions by type of breastfeeding problem 
(Cumulative; Months 1, 3, 5) 
New 
Both 
Table: Percentage distribution of possible solutions to barriers (Cumulative,  
Months 1, 3,5) 
New 
Both 
Table: Percentage of mothers receiving breastfeeding education/support (WIC vs. 
elsewhere) by breastfeeding decision (Cumulative, Months 1, 3) 
New 
Both 
Figure: Median age of breastfeeding cessation, age when 25% and age when 75% 
of the infants are weaned from the breast (Cumulative: Months 1-13) 
IFPS-1 p163 
Both 
Figure: Percentage of all WIC mothers breastfeeding, by age of the infant  
(Months 1-13) 
IFPS-1 p164 
Both 
Continuation and Cessation of Breastfeeding 
Figure: Percentage of all WIC mothers still breastfeeding, by age of the 
infant and age of the mother (Months 1-13) 
IFPS-1 p165 
Both 
Figure: Percentage of all WIC mothers still breast-feeding, by age of the infant 
and whether the mother reports knowing about the special WIC food package for 
breastfeeding women who do not accept infant formula for WIC (Months 1-13) 
IFPS-1 p166 
Both 
Table: Frequency of top 10 reasons women stop breastfeeding within the first 2 
and 6 weeks (Cumulative; Months 1, 3)  
New  
Both 
Table: Frequency of top 5 reasons women stop breastfeeding within the first 6 
weeks by infant health status and household demographics (Cumulative; Months 
1, 3) 
New  
Both 
Table: Frequency of top 5 reasons women stop breastfeeding by the magnitude of 
the difference between intended and actual breastfeeding duration 
New 
Both 
Table: Percentage distribution of reasons for stopping breastfeeding between 2-
3and 4-6 months (Months 3, 5,7) 
New 
Both 
Table: Average Edinburgh Postpartum Depression Scale score by breastfeeding 
status (Month 3 )  
New 
Both 
Table: Characteristics and circumstances of mothers breastfeeding (Months 1, 7) 
New 
Both 
Table: (Model) Relative risks estimated by the multivariate models of rates of 
breastfeeding cessation (survival analysis) (Months 1-13) 
IFPS-1 
p168p168 
Both 
Figure: Percentage of WIC mothers still breastfeeding by age of the infant and 
reported receipt of none, one, two, or three WIC program components that 
support breastfeeding (Months 1-13) 
IFPS-1 p173 
Both 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-16 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Initiation of Supplemental Foods: The Transitional Phase of Infant Feeding 
Table: Infant feeding patterns of WIC participants (by milk/food category)  
(Months 3-11) 
FITSd S74 
Both 
Figure: Percentage of WIC mothers who have not yet initiated cereals, fruits, 
vegetables, and meats at each age of the infant (Months 1-13) 
IFPS-1 p186 
Both 
Figure: Percentage of WIC mothers who have not yet initiated dairy foods, high-
protein foods other than meats, and sweet/snack foods, at each age of the infant 
(Months 1-13) 
IFPS-1 p188 
Both 
Table: Median age of the infant (in weeks) when specific supplemental foods are 
initiated by selected socio-demographic characteristics of the mother 
(Cumulative; Months 1-13) 
IFPS-1 p189 
Both 
Table: Percentage of infants and toddlers consuming different types of milk and  
other beverages by age (Months 3-24) 
FITS S40 
 
Both 
Table: Percentage distribution of combination feedings by age (Months 1-13) 
New 
Both 
Figure: Percentage of WIC mothers who have not yet initiated cereals at each age 
of the infant, by maternal immigrant status (Months 1-13) 
IFPS-1 p190 
Both 
Figure: Percentage of mothers initiating cereals, fruits, vegetables, and meats as 
the first, second, third or fourth type of supplemental food (Cumulative; Months  
1-13) 
IFPS-1 p192 
Both 
Table: Percentage distribution of the order of initiation of cereals, fruits, 
vegetables, and meats, by race/ethnicity of the mother (Cumulative;  
Months 1-13) 
IFPS-1 p194 
Both 
Table: (Model) Relative risk of initiating cereals prior to four and six months of age 
(survival analysis) (Months 1-13)  
IFPS-1 p196 
Both 
Table: (Model) Relative risk of initiating fruits prior to four and six months of age 
(survival analysis) (Months 1-13) 
IFPS-1 p199 
Both 
Table: (Model) Relative risk of initiating vegetables prior to four and six months of 
age (survival analysis) (Months 1-13) 
IFPS-1 p201 
Both 
Figure: Percentage of WIC mothers who have not yet initiated fruit juices, sweet 
drinks, and cow milk or other milk at each age of infant (Months 1-13) 
IFPS-1 p207 
Both 
Table: Median age of the infant at the time of initiation of fruit juices or sweet 
drinks by selected socio-demographics (Cumulative; Months 1-13) 
IFPS-1 p208 
Both 
Figure: Percentage of WIC mothers who have not yet introduced sweet drinks at 
each age of infant, by race/ethnicity of the mother(Months 1-13) 
IFPS-1 p209 
Both 
Table: Average infant age mother previously introduced solid foods (cereal and 
other) to siblings (Baseline) 
New 
Both 
Table: Transitions in infant and toddler feeding among toddlers 12 to 24 months 
(Cumulative; Months 11-24) 
FITSd S74 
Both 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-17 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Supplemental Foods and Feeding Practices 
Table: Percentage of distribution of food preparation methods used by caregivers 
(Months 7, 9, 11,13) 
New 
Both 
Table: Percentage distribution of the impacts of food package choice on food 
child receives (Months 7, 15) 
New 
Both 
Table: Percentage distribution of sources of baby food (Months 7-13) 
New 
Both 
Table: Share of purchased baby food covered by WIC vouchers (Months 7-13) 
New 
Both 
Table: Percentage distribution of food choices across feedings (morning, 
afternoon, evening) (Months 1-13) 
New 
Both 
Table: Methods of feeding supplemental foods at interview months when data 
was elicited (Months 3-18)  
IFPS-1 p215 
Both 
Figure: Percentage of WIC infants receiving supplemental foods using a spoon by 
race and ethnicity of the mother (Months 3-9) 
IFPS-1 p216 
Both 
Figure: Percentage of WIC mothers who have used an infant feeder sometime 
during infancy by race and ethnicity of the mother (Cumulative, Months 3-11)  
IFPS-1 p217 
Both 
Table: Percentage of WIC mothers who adopt supplemental food feeding 
practices that are generally not recommended (Cumulative; Months 1-5) 
IFPS-1 p218 
Both 
Figure: Percentage of WIC mothers who feed supplemental foods before month 
4prior to using a spoon, by race and ethnicity of the mother (Month 3) 
IFPS-1 p220 
Both 
Table: Self feeding skills and the percentage of toddlers who were reported to 
show the self feeding skill by age (Months 9, 11, 13, 18) 
FITSe S53 
Both 
Table: Average number of months using a bottle by socio-
demographics(Cumulative; months7-24) 
New 
Both 
Feeding Practices, Working, and Childcare 
Table: Number of caregivers who work or go to school  
(Months 3, 7, 13, 18, 24)  
New 
Both 
Table: Percentage distribution of children in childcare by types of childcare  
(Months 3, 7, 13, 24) 
New 
Both 
Table: Average age of child when they first started childcare by type of childcare 
(Cumulative; Months 3, 7, 13, 24) 
New 
Both 
Table: Frequency of barriers to breastfeeding children in childcare  
(Cumulative; Months 3, 7,) 
New 
Both 
Table: Percentage of mothers with children in childcare who go to facility to 
breastfeed during the day (Cumulative; Months 3, 7) 
New 
Both 
Table: Percentage distribution of who provides the food for the child by type of 
childcare (Months 3, 7, 13, 24) 
New 
Both 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-18 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Feeding Practices, Working, and Childcare (continued) 
Table: Percentage of children in childcare getting human milk by age of infant 
and method of receipt (Months 3, 7) 
New 
Both 
Table: Percentage distribution of accommodations available at work to assist with 
pumping milk (Month 3)  
New 
Both 
Nutritional Intake 
Table: Percentage of WIC infants who receive each of the 13 groups of food at 
each age (Months 1-13) 
IFPS-1 p225 
Both 
Table: Percentage of infants and toddlers consuming grains, vegetables, fruits, 
and meats/other protein sources, and desserts, sweets, sweetened beverages 
and salty snacks by age (Months 3-24) 
New 
Both 
Table: Percentage of infants and toddlers consuming different types of grain 
products by age (Months 3-24) 
FITSa S42 
Both 
Table: Percentage of infants and toddlers consuming different types of fruits 
products by age (Months 3-24) 
FITSa S43 
Both 
Table: Top five fruits consumed by infants and toddlers by age (Months 3-24)  
FITSa S44 
Both 
Table: Percentage of infants and toddlers consuming different types of vegetables 
by age (Months 3-24)  
FITSa S45 
Both 
Table: Top five fruits vegetables consumed by infants and toddlers by age (Months 
3-24)  
FITSa S46 
Both 
Table: Percentage of infants and toddlers consuming meats or other protein 
sources by age (Months 3-24) 
FITSa S47 
Both 
Table: Percentage of infants and toddlers consuming desserts, sweets, sweetened 
beverages, and salty snacks, by age (Months 3-24) 
FITSa S48 
Both 
Table: Usual nutrient intake distributions of infants: Micronutrients (Months 3,5 & 
7,11) 
FITSb S16 
Both 
Table: Usual nutrient intake distributions of toddlers 12 to 24 months (Months 13-
24) 
FITSb S17 
Both 
Table: Estimated energy requirements and usual intake of food energy, infant and 
toddlers (Months 5-24) 
FITSb S17 
Both 
Table: Usual nutrient intake distributions: Macronutrients (Months 5-24) 
FITSb S18 
Both 
Table: Usual intake of dietary fiber (Months 5-24) 
FITSb S19 
Both 
Table: Mean intakes of selected nutrients by source of milk (Month 5) 
FITSb S20 
Core 
Table: Mean intakes of selected nutrients by source of milk (Month 5) 
FITSb S20 
Core 
Figure: Percentage of infants and toddlers participating in nonmeal eating 
occasions (Months 7-24) 
FITSc S66 
Both 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-19 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Nutritional Intake (continued) 
Table: Percentage of total energy from each eating occasion by age category for 
infant and toddlers (Months 3-24) 
FITSc S66 
Both 
Table: Macronutrient distributions at meals and snacks by age category (Months 
7-24) 
FITSc S67 
Both 
Table: Nutrient density: vitamin A, C, D, foliate, Ca, Fe per 1000 Kcals and fiber 
(Months 7-24) 
FITSc S67 
and new 
Both 
Table: Most frequently eaten foods at each eating occasion by age category 
(Months 3-24) 
FITSc S68 
Both 
Child’s Weight and Feeding Practices 
Table: Percentage of children in each weight/length quintile by breastfeeding 
experience for months 6, 12, and 24 (Months 1, 3 and clinical records 6, 12, 24) 
New 
Both 
Table: Percentage of children (at 24 months) in each weight/length quintile by 
timing of the introduction of different types of solid foods (Cumulative; Months 1-
13 & clinical records 24) 
New 
Both 
Table: Child’s weight/length quintile at 24 months by mothers average sweetened 
beverage and fruit and vegetable intake score (Month 24) 
New 
Both 
Table: Percentage of children in top 20% and bottom 20% of the weight/length 
distribution at 12 and 24 months by breastfeeding experience and socio-
demographics (Months 1, 3 and clinical records 12, 24) 
New 
Both 
Table: Percentage of children in top 20% and bottom 20% of the weight/length 
distribution at 12 and 24 months by child’s health, physical activity behavior, and 
rearing/feeding practices (Cumulative, Months 1-24 and clinical records 12, 24) 
New 
Both 
Table: Average child weight/length gain in first 6 months by breastfeeding 
experience and gender (Months 1, 3 and clinical records 1, 6) 
New 
Both 
Table: Average child weight/length gain in first 6-12 months by breastfeeding 
experience and gender (Months 1, 3 and clinical records 6, 12) 
New 
Both 
Table: (Model) OLS regression estimates of the impact of the impact of socio- 
demographics and feeding practices on weight/length at 24 month (Cumulative; 
Months 1-24 and clinical records for 6, 12 24) 
New 
Both 
Table: (Model) Quantile regression estimates of the impact of socio- 
demographics and feeding practices on weight/length at 6 month (Cumulative; 
Months 1-6 and clinical records for 6) 
New 
Both  
Table: (Model) Quantile regression estimates of the impact of socio- 
demographics and feeding practices on weight/length at 12 month (Cumulative; 
Months 1-13 and clinical records for 6, 12) 
New 
Both  
Table: (Model) Quantile regression estimates of the impact of socio- 
demographics and feeding practices on weight/length at 24 month (Cumulative; 
Months 1-24 and clinical records for 6, 12 24) 
New 
Both  

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-20 
 
Table 7-2. 
Summary of analyses to be conducted (continued) 
 
Table/Figure (interview months) 
Source 
Sample 
Child’s Weight and Feeding Practices (continued) 
Table: (Model) Growth model estimates of the impact of socio- demographics and 
maternal health on weight gain trajectory of the child from birth to 2 years 
(Cumulative; Months 1-24 and clinical records for 0, 6, 12 24) 
New 
Both 
 
We will also provide estimates of the measures used in the tables and figures listed above (in Table 
7-2) by key subgroups. Some of the variables of interest are summary measures that are relevant to 
the entire population and therefore well suited to examining differences between subgroups. Key 
subgroups include: 
 
 
Race  
 
Ethnicity 
 
Age of mother 
 
Marital status 
 
Food security 
 
Participation in other benefit programs 
 
Parity 
 
Birthweight 
 
Birth complications 
 
Type of delivery 
 
Hospital length of stay 
 
Breastfeeding (history) group  
 
WIC prenatal (joined) WIC trimester (joined) 
 
Interpartum (<27 months, 27-68 months, > 69 months)19  
 
WIC exposure of the mother 
 
Weight status of mother 
                                                
19Our data only allows us to measure the time between the last birth and current birth 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-21 
 
 
Income poverty 
 
Child’s WIC participation status 
 
Continuity of WIC participation 
 
Nature/intensity of breastfeeding support at hospital 
 
Nature/intensity of breastfeeding support at home 
 
Nature/intensity of breastfeeding support at from WIC 
 
Nature/intensity of breastfeeding support at work 
 
Nature/intensity of breastfeeding support at childcare 
 
Nature/intensity of nutrition education and skills training 
Not all the subgroups are applicable to every response measure of interest. Additionally, some 
measures of interest only apply to a subset of the population. Therefore, in selecting the subgroups 
to use for each table and figure, we will consider whether they are likely to be correlated with 
response measure of interest. In Appendix C, we provide example sets of table shells detailing how 
we would provide and display subgroup estimates for 3 of the tables listed in Table 7-2. 
 FITS studies as well as some additional analyses we believe are also important. In Appendix A, we 
provide a mapping of the relevant analyses to each research question to demonstrate that the study 
will answer all 60 questions.  
 
Table 7-2 is a list of all the tables or figures by title. Following the title in parenthesis, we list the 
WIC participant survey interview months to be used in the analysis. Many tables are repeating the 
work of the IFPS-1 study or the FITS study and the specific publication and source page for the 
original table is provided to allow for cross-referencing20.  
 
                                                
20 IFPS refers to Baydar, et al. Final Report: WIC Infant Feeding Practice Study, November 1997.  
 FITSa refers to Seiga-Riz, Anna Marie et al. Food Consumption Patterns of Infants and Toddlers: Where are we Now? in the Supplement to the Journal 
of the American Dietetic Association, 2010. 
 FITSb refers to Devaney, Barabara et al. Nutrient Intakes of Infants and Toddlers in the Supplement to the Journal of the American Dietetic Association, 
2004. 
 FITSc refers to Skinner, Jean D. et al. Meal and Snack Patterns of Infants and Toddlers in the Supplement to the Journal of the American Dietetic 
Association, 2004. 
 FITSd refers to Ponza, Micheal et al. Nutrient Intakes and Food Choices of Infants and Toddlers and Toddlers Participating in WIC in the 
Supplement to the Journal of the American Dietetic Association, 2004. 
 FITSe refers to Carruth, Betty Ruthet al. Developmental Milestones and Self-Feeding Behaviors in Infants and Toddlers in the Supplement to the 
Journal of the American Dietetic Association, 2004. 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-22 
 
 
Model Specifications 
Several of the specific analyses shown in Table 7-2 involve estimating models. Table 7-3 provides 
the detailed specifications for these models. The first four models – the breastfeeding decision 
model, the formula supplementation model, the breastfeeding cessation model, and introduction of 
other foods model -- mirror models used in the previous IFPS-1 study. Initially, we will estimate 
these models primarily using the covariates that were used in the IFPS-1 study. This will facilitate the 
comparisons to the past research. We will also explore extending this work by making some 
improvements in the measurement of variables, the estimation method, and the covariates used. For 
these models, the additional covariates and estimation methods we propose to explore are noted in 
italics on Table 7-3. For many of the explanatory variables there are alternative proxy variables that 
we could use to measure the concept we are trying to capture. We will explore these alternative 
proxies if the initial variable proves to be insignificant. The weight and growth models shown in 
Table 7-3 are new. 
 
Table 7-3. 
Proposed model specifications 
 
Model 
Dependent 
variable 
Estimation 
methods 
Minimum covariates to explore  
Breastfeeding 
decision 
 Initiating 
breastfeeding 
 Breastfeeding 
at hospital 
discharge 
Measured 
dichotomously 
and categorically 
(all breastfeeding, 
combination, all 
formula) 
 Logistic 
regression 
(dichotomou
s) 
 Multinomial 
logistic 
regression 
(categorical) 
 Socio-demographics: Age, race/ethnicity, 
born in US, father in house, infant first born, 
income, poverty level, education, worked 
during pregnancy 
 Maternal and infant health: Mother’s post-
delivery health status, infants health status 
(measured as in NICU or more than 6 weeks 
premature or very low birth weight) 
 Prenatal attitudes, beliefs and knowledge: 
Perceived benefits of breastfeeding, 
perceived barriers, breastfeeding intentions 
 Prenatal experience and advice: breastfed 
previous children, receipt of advice to 
breastfeed from physician, receipt of advice 
to breastfeed from family, receipt of 
breastfeeding information from non-WIC 
sources 
 WIC program experience: Education, peer 
counseling, time in WIC 
 Hospital experience: Mom’s length of stay, 
baby’s length of stay, receipt of formula or 
bottle in gift package, had baby friendly 
practices 
 
 
Breastfeeding 
Initiating 

decision
breastfeeding
Logistic 
Socio-demographics: Age, race/ethnicity,

regression 
born in US, father in house, infant first born,
(dichotomou
income, poverty level, education, worked 
s)
during pregnancy
Multinomial
Maternal and infant health: Mother’s post-t


logistic 
delivery health status, infants health status
regression 
(measured as in NICU or more than 6 weeks 
(categorical)
premature or very low birth weight)
Prenatal attitudes, beliefs and knowledge:

Perceived benefits of breastfeeding, 
perceived barriers, breastfeeding intentions
Prenatal experience and advice: breastfed

previous children, receipt of advice to 
breastfeed from physician, receipt of advice 
to breastfeed from family, receipt of
breastfeeding information from non-WIC
sources
WIC program experience: Education, peer

counseling, time in WIC

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-23 
 
Table 7-3. 
Proposed model specifications (continued) 
 
Model 
Dependent 
variable 
Estimation 
methods 
Minimum covariates to explore  
Formula 
Supplementation 
 Time until 
formula 
supplementati
on 
 Survival 
analysis 
 Socio-demographics: Age, race/ethnicity, 
born in US, infant first born, use of childcare, 
education, worked during pregnancy 
 Maternal and infant health: Mother’s post-
delivery health status, infants health status, 
birth weight, reported problems 
breastfeeding 
 Prenatal attitudes, beliefs and knowledge: 
Perceived benefits of breastfeeding, 
perceived barriers, how long intend to 
breastfeed 
 Prenatal experience and advice: Receipt of 
advice to breastfeed from physician, receipt 
of breastfeeding information from non-WIC 
sources  
 WIC program experience: Education, peer 
counseling, breast pumps, time in WIC 
Breastfeeding 
cessation 
 Time until 
cessation 
 Survival 
analysis 
 Socio-demographics: Age, race/ethnicity, 
born in US, infant first born, education, use of 
child care  
 Maternal health: Reported breastfeeding 
problems 
 Breastfeeding practices: Current use of 
formula 
 Prenatal attitudes, beliefs and knowledge: 
Perceived benefits of breastfeeding, 
perceived barriers, how long intend to 
breastfeed 
 Prenatal experience and advice: Receipt of 
advice to breastfeed from physician, receipt 
of breastfeeding information from non-WIC 
sources 
 WIC program experience: Education, peer 
counseling, breast pumps, time in WIC 
 Return to work/school: Returned to 
work/school within 2 months  
Introduction of 
other foods 
 Time until 
cereal 
 Time until 
fruits 
 Time until 
vegetables 
 Time until 
meats 
 Survival 
analysis 
 Socio-demographics: Age, race/ethnicity, 
born in US, household size, income, poverty 
level, use of child care, returned to work or 
school, education 
 Feeding practices: current use of formula 
 Attitudes, beliefs and knowledge: Belief 
formula provided from WIC is insufficient, 
parental assessment of baby’s weight  
 Prenatal experience and advice: Receipt of 
breastfeeding information from non-WIC 
sources 
 
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-24 
 
Table 7-3. 
Proposed model specifications (continued) 
 
Model 
Dependent 
variable 
Estimation 
methods 
Minimum covariates to explore  
 
  
  
 WIC program experience: Education, time in 
WIC 
 Return to work/school: Returned to 
work/school within 2 months 
Weight 
 Child’s 
weight/length 
(6, 12, and 24 
months) 
 OLS  
 Quantile 
regression 
 
 Socio-demographics: Gender, race/ethnicity, 
income, born in US 
 Maternal/family health: Maternal BMI, 
paternal obesity, maternal diabetes, smoking 
during pregnancy, household food security 
(24 months only), maternal fruit and 
vegetable dietary intake (24 months only) 
 WIC program experience: Education, food 
package, time in WIC (and peer counseling 
for 6 month weight/length) 
 Child’s health and physical activity: birth 
weight, premature, rapid early weight gain, 
physical activity indoors, physical outdoors 
(for 24 month measure) current sleep 
duration  
 Basic dietary intake: Breastfeeding duration, 
current intake of sweetened beverages 
 Feeding practices: Clean plate policy, track 
eating, careful not to feed too much 
Growth  
 Repeated 
measures of 
child’s 
weight/length  
 Growth 
model 
 Socio-demographics: Gender, race/ethnicity, 
income Maternal/family health: Maternal 
BMI, paternal obesity, maternal diabetes, 
smoking during pregnancy 
 WIC program experience: Education, food 
package, time in WIC 
 Child’s health and physical activity: Birth 
weight, premature 
 Basic dietary intake: Breastfeeding duration 
 
We will estimate several variants of the breastfeeding decision model. First, we will use two 
alternatives for the dependent variable: initiating breastfeeding and breastfeeding at hospital 
discharge. Similarly, we will explore using dichotomous measures (yes, no) for these variables as well 
using categorical measures that capture mixing breastfeeding and formula feeding from the start. 
Additionally, we will have mother’s prenatal attitudes collected prior to delivery (rather than 
retrospectively) and can also explore how their breastfeeding intentions for initiation and duration 
affect actual initiation and exclusivity. Finally, for this model we will explore the viability of using a 
summary index to capture the mother’s attitudes, beliefs, and knowledge on breastfeeding and her 
hospital experience in place of the individual covariates in these groups.  
 

Analysis 7 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-25 
 
Our estimates of the formula supplementation model and time until the introduction of other foods 
models will closely parallel the past work with few extensions. In estimating the formula 
supplementation model we will explore how breastfeeding intentions regarding duration (which is 
typically not collected) affect the time until formula supplementation. The covariates we will 
examine for predicting the time until breastfeeding cessation and the introduction of cereals, fruits, 
and vegetables will parallel those used in the IFPS-1 study. 
 
For the new weight model, we will run separate models estimating weight/length for the children at 
6, 12, and 24 months. In addition to including direct measures of toddler feeding practices (such as 
family has a clean plate policy), we will explore the viability of using summary measures of a range of 
toddler feeding practices to predict weight outcomes. 
 
Finally, in all these models we will capture the cross-sectional variation in the WIC program 
experience through the inclusion of WIC program composite measures which will be an 
enhancement over past studies. For breastfeeding initiation and duration decisions, we expect that 
the variation in educational programs, peer counseling and the provision and support for breast 
pumps will be factors affecting individuals’ decision. For infant feeding transitions and toddler 
weight outcomes, we expect that variation in education and the food packages will be important 
factors. For all of these decisions and outcomes, we expect that the time the mother has spent in 
WIC will be an important predictor. 
 
Finally, in all these models we will capture the cross-sectional variation in the WIC program
experience through the inclusion of WIC program composite measures which 
For breastfeeding initiation and duration decisions, we expect that 
the variation in educational programs, peer counseling and the provision and support for breast 
pumps will be factors affecting individuals’ decision.

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
7-26 
 
This page left intentionally blank

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
8-1 
 
Table 8-1 provides a summary of our proposed analytical report schedule and the content of each 
report. There are a few topic areas that draw solely from data collected during the first few 
interviews and these analyses can be completed prior to finishing all the data collection. Analyses of 
prenatal views, the study design and sample, breastfeeding decisions, hospital practices and neonatal 
circumstances, and breastfeeding problems can be completed prior to conducting the 13 months 
interview. Additionally, the analyses on formula supplementation, breastfeeding and formula feeding 
practice, and the continuation and cessation of breastfeeding can be completed using data through 
the month 13 interview. The analyses of all the other topic areas at least partially depend on data 
collected from later interviews. Therefore, as our report schedule shows, there are some topics for 
which we will provide preliminary analysis based on the currently available data and then update 
these analyses in final infant and final infant and toddler reports. Please note, that while we are 
contracted to deliver 4 interim reports on the toddler interviews, since FNS eliminated the 21 month 
interview, we have only 3 data collection interviews. We have some suggestions for the content of 
the 4th report we would like to discuss with FNS. 
 
Table 8-1. 
List of analytical reports 
 
Reports 
Main topic 
Content/ 
Data cutoff 
Report 
Infant interim 1 
Intention to 
breastfeed 
Prenatal views/  
Results through prenatal interview 
 
1/11/2014 
Infant interim 2 
Initiation of 
breastfeed 
Study design and sample  
Breastfeeding decisions 
Hospital practices and neonatal circumstances/ 
Result through 3 month interview 
 
10/10/2014 
Infant interim 3 
Breastfeeding and 
formula 
supplementation 
Knowledge attitudes , and sources of information 
(initial data) 
Breastfeeding problems 
Formula supplementation (initial data) 
Breastfeeding and formula feeding practices (initial data)/ 
Results through 7 month interview  
 
2/13/2015 
 
 
Analysis Reports 8 

Analysis Reports 8 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
8-2 
 
Table 8-1. 
List of analytical reports (continued) 
 
Reports 
Main topic 
Content/ 
Data cutoff 
Report 
Infant interim 4 
Infant Feeding 
Practices, 
Introduction to  
Solid Foods 
Mother/Caregivers WIC experience (initial data)  
Continuation and cessation of breastfeeding 
Initiation of supplemental foods: the transition phase  
of infant feeding (initial data)/ 
Results through 13 month interview 
 
8/14/2015 
Infant final 
1st Year Feeding 
Practices 
All topics listed above (topics with initial data will be 
updated through 13 month interview ) 
 
10/9/2015 
Toddler interim 1 
Nutrient Intake & 
Weight Gain 
Nutritional intake (initial data) 
Child’s weight and feeding practices (initial data)/ 
Results through 15 month interview 
 
10/9/2015 
Toddler interim 2 
Supplemental foods 
and feeding practices 
Supplemental foods feeding practices(initial data)/ 
Results through 18month interview 
 
1/8/2016 
Toddler interim 3 
Feeding practices, 
working and 
childcare 
 
Feeding practices, working, and childcare (initial data)/ 
Results through 24 month interview 
4/1/2016 
Toddler interim 4 
Nutrient Intake & 
Weight Gain 
Nutritional intake 
Child’s weight and feeding practices  
Results through 24 month interview 
 
4/1/2106 
Infant/Toddler 
final 
1st & 2nd Year 
Feeding Practices 
All topics (all topics with initial data will be updated 
through 24 month interview) 
5/20/2016 
 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
R-1 
 
References 
 
Ernst, L.R. and Williams, T.R. (1987). Some aspects of estimating variances by half-sample 
replication in CPS. Proceedings of the Section on Survey Research Methods of the American Statistical 
Association, pp. 480-485.  
Folsom, R.E. and Witt, M.B. (1994). Testing a new attrition nonresponse adjustment method for 
SIPP. Proceedings of the Section on Survey Research Methods of the American Statistical Association, pp. 
428-433.  
Judkins, D. (1990). Fay's method for variance estimation. Journal of Official Statistics, 6, 223-239. 
Judkins, D. (1997). Imputing for Swiss cheese patterns of missing data. Proceedings of Statistics Canada 
Symposium ‘97, 143-148. 
Judkins, D., Hao, H. Barrett, B., and Adhikari, P. (2005). Modeling and polishing of nonresponse 
propensity. Proceedings of the Section on Survey Research Methods of the American Statistical Association, 
pp. 3159-3166. 
Judkins, D., Krenzke, T., Piesse, A., Fan, Z., and Haung, W.C. (2007). Preservation of skip patterns 
and covariance structure through semi-parametric whole-questionnaire imputation. Proceedings 
of the Section on Survey Research Methods of the American Statistical Association, 3211-3218. 
Judkins, D., Piesse, A., and Krenzke, T. (2008). Multiple semi-parametric imputation. Proceedings of the 
Joint Statistical Meetings [CD-ROM], pp. 48-58. Alexandria, VA: American Statistical 
Association.  
Krenzke, T. and Judkins, D. (2008). Filling in blanks: Some guesses are better than others – 
Illustrating the impact of covariate selection when imputing complex survey items. Chance, 21(3), 
7-13.  
Marker, D. A., Judkins, D. R., and Winglee, M. (2001). Large-scale imputation for complex surveys, 
in Survey Nonresponse, Eds. R. M. Groves, D. A. Dillman, E. L. Eltinge, and R. J. A. Little. New 
York: Wiley.  
Piesse, A., Judkins, D., and Fan, Z. (2005). Item imputation made easy. Proceedings of the Section on 
Survey Research Methods of the American Statistical Association, pp3476-3479. 
Rizzo, L. and Judkins, D. (2004). Replicate variance estimation for the National Survey of Parents 
and Youth. Proceedings of the Section on Survey Research Methods of the American Statistical Association, 
pp. 4257-4263. 
Rizzo, L., Kalton, G., Brick, M. (1996). A comparison of some weighting adjustments for panel 
nonresponse. Survey Methodology, 22, 43-53.  

References 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
R-2 
 
Zador, P., Judkins, D., and Das, B. (2001). Experiments with MART to Automate Model Building in 
Survey Research: Applications to the National Survey of Parents and Youth. Proceedings of the 
Section on Survey Research Methods of the American Statistical Association 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-1 
 
Appendix A 
Summary of WIC-IFPS-1 Analyses to be Repeated 
 
Table A-1 provides a listed of all the tables and figures in the WIC-IFPS-1 final report in terms of 
the order in which they appear in the document. To facilitate cross-referencing to the WIC-IFPS-1 
final report, we note the page on which the table or figure appears. We specify if we are repeating 
the analysis and note major deviations. In cases in which we will not repeat the analysis, we provide 
an explanation as to why. 
 
Table A-1. 
List of WIC-IFPS-1 report tables and figures  
 
Table/Figure 
Page 
Status 
CHAPTER I: INTRODUCTION AND OVERIVIEW 
This chapter contains no tables or figures 
CHAPTER II: STUDY DESIGN AND SAMPLE 
Table II.1 Overall study participation counts and rates 
20 
Will repeat  
Table II.2 Counts and percent of respondents by sample type 
and interview month 
21 
Will repeat 
Table II.3 Percentage distribution of socio-demographic 
characteristics by maternal race and ethnicity 
25 
Will repeat  
Table II.4 Percentage distribution of reported health-related 
characteristics by maternal race and ethnicity of the mother 
26 
Will repeat 
Table II.5 Percentages of mothers reporting the receipt of WIC 
vouchers for formula and supplemental foods 
27 
Will not repeat. Replaced by table on 
food packages  
Table II.6 Percentages of mothers reporting receipt of 
information about various aspects of infant feeding from WIC 
28 
Will repeat  
CHAPTER III: CONCEPTUAL MODEL AND APPROACH TO ANALYSIS 
Table III.3 WIC-IFPS data on infant feeding practices in the 
nursing phase 
31 
Will not repeat but rather replace with 
a discussion of the variables we will 
collect 
Table III.2 WIC-IFPS data on infant feeding practices in the 
transitional phase 
33 
Will not repeat but rather replace with 
a discussion of the variables we will 
collect 
Figure III-1 A general model of infant feeding practices and 
the measures of predictors of infant feeding practices from 
WIC-IFPS 
38 
Will replace with graphics of updated 
model 
CHAPTER IV: CHOICE BETWEEN BREATFEEDING AND FORMULA FEEDING  
Figure IV.1 A model of breastfeeding initiation and the 
measures of its predictors available from the WIC-IFPS  
46 
Will replace with graphics of updated 
breastfeeding decision model 
Table IV.1 Breastfeeding initiation rates by selected socio-
demographic and health-related characteristics 
53 
Will repeat  
Figure IV.2 Breastfeeding initiation rates, by race and 
ethnicity of the mother  
54 
Will repeat 
Table IV.2 Estimates of the relative odds estimated by the 
logistic regression model of breast feeding initiation  
58 
Will repeat similar content but models 
will differ  
 
 

Appendix A 
Summary of WIC-IFPS-1 Analyses to be Repeated 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-2 
 
 
Table A-1. 
List of WIC-IFPS-1 report tables and figures (continued) 
 
Table/Figure 
Page 
Status 
Figure IV.3 Relative odds of initiating breastfeeding for WIC 
mothers who received breastfeeding information and advice 
from different sources 
63 
Will repeat similar content but specific 
categories for sources of information 
will differ 
Table IV.3 Items that constitute the perceived benefits of 
breastfeeding and perceived barriers to breastfeeding scales 
(factor analysis) 
71 
Will repeat applying factor analysis but 
the items will differ 
Table IV.4 Percentage of mothers agreeing with the nine 
statements about perceived benefits of breastfeeding 
73 
Will repeat but the items will differ 
Table IV.5 Percentage of mothers agreeing with the 13 
statements about perceived barriers to breastfeeding 
74 
Will repeat but the items will differ 
Figure IV.4 A model of initiation of formula supplementation 
and the measures of the predictors available from the WIC-
IFPS 
82 
Will replace with graphics of updated 
breastfeeding duration model 
Figure IV.5 Percentages of only breastfeeding, combined 
breast-and formula feeding, and only formula-feeding WIC 
mothers at each month of interview 
88 
Will repeat  
Table IV.6. Percentage distribution of the infants by nursing 
diets at the at the time of each interview month; by selected 
socio-demographic characteristics  
90 
Will repeat  
Figure IV.6 Percentages of breastfeeding WIC mothers, by 
type of breastfeeding practice at each month of interview  
92 
Will repeat  
Figure IV.7 Percentage of breastfeeding WIC mothers who 
have not yet initiated formula, by the age of the infant 
94 
Will repeat 
Table IV.7 Median age in days of the infant at the time when 
formula supplementation is initiated, by selected socio-
demographic characteristics  
94 
Will repeat but measure child’s age in 
weeks not days 
Table IV.8 Estimates of the relative risk estimated by the 
multivariate models of rates of formula supplementation 
(survival analysis) 
96 
Will repeat similar content but models 
will differ 
CHAPTER V:HOSPITAL PRACTICES AND NEONATAL CIRCUMSTANCES EXPEREINCE BY MOTHERS 
Figure V.1 A model of feeding practices at hospital discharge 
and the measures of its predictors available from the WIC-
IFPS  
103 
Will replace with graphics of updated 
breastfeeding decision model (for 
hospital) 
Figure V.2Number of days of hospital stay for WIC mothers 
and infants  
109 
Will repeat  
Figure V.3 Percentage of WIC infants who stayed in the 
nursery overnight 
109 
Will repeat 
Table V. 1 The first feeding received by WIC infants in the 
hospital 
110 
Will repeat 
Figure V. 4 The first feeding of WIC infants in the hospital, by 
race and ethnicity of the mother  
111 
Will repeat  
Table V.2 Percentages of mothers reporting nursing problems 
while in the hospital  
113 
Will repeat  
Figure V.5 Percentage of WIC mothers who did not receive 
help from the hospital staff among those who had common 
nursing problems  
114 
Will repeat  
Figure V.6 Percentage of WIC mothers who reported receiving 
115 
Will repeat  

Appendix A 
Summary of WIC-IFPS-1 Analyses to be Repeated 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-3 
 
Table A-1. 
List of WIC-IFPS-1 report tables and figures (continued) 
 
Table/Figure 
Page 
Status 
various items in their gift packages from the hospital 
Table A-1. 
List of WIC-IFPS-1 report tables and figures (continued) 
 
Table/Figure 
Page 
Status 
Table V.3 Percentage of type of feeding at hospital discharge 
by type of first feeding 
116 
Will repeat 
Table V.4 Relative odds of formula feeding at hospital 
discharge for WIC mothers who breastfeed at the first feeding 
118 
Will repeat similar content but models 
will differ 
Table V.5 Relative odds of breastfeeding at hospital discharge 
for WIC mothers who formula feed at the first feeding 
120 
Will repeat similar content but models 
will differ 
CHAPTER VI: BREASTFEEDING AND FORMULA FEEDING PRACTICES  
Figure VI.1 A model of daily number of breastfeeds at Month 
1 interview and its predictors available from the WIC-IFPS  
126 
Will not repeat as not deemed to be 
highly critical outcome 
Table VI.1 Breastfeeding schedules of WIC mothers over the 
first five months of their infants’ first year  
128 
Will repeat  
Figure VI.2 Percentage of WIC mothers who breast feed on a 
set schedule, when the infant cries or seems hungry, and on a 
mixed schedule 
130 
Will repeat  
Table VI. 2 Usual number of daily breastfeeds, by selected 
maternal socio-demographic characteristics 
131 
Will repeat  
Table VI.2Percentage of WIC mothers who report expressing 
milk during the past week, by selected maternal socio-
demographics 
132 
Will repeat  
Figure VI.3 Percentage of breastfeeding WIC mothers 
expressing milk, using electric breast pumps, using manual 
breast pumps, and expressing milk by hand  
133 
Will repeat (excluding type of pump) 
Table VI.4 Relative contribution of selected non-program and 
program factors to the usual number of daily breastfeeds 
reported at Month 1 interview  
135 
Will repeat similar content but models 
will differ 
Table VI.5 Percentage of WIC mothers who add other foods or 
liquids into the bottle with the formula by selected socio-
demographic characteristics  
141 
Will repeat 
Figure VI.4 Percentage of mothers who report adding other 
foods or liquids in the bottle with the formula at Month 3 
142 
Will repeat  
Figure VI.4 Percentage of mothers who report adding other 
foods in the bottle with formula at Month 1 among those who 
think that the amount of formula given by WIC is more than 
enough, the right amount, or not enough  
143 
Will repeat  
 
Table VI.5 Percentage distribution of formula-feeding WIC 
mothers by brand name of formula  
145 
Will repeat  
 
CHAPTER VII: FEEDING PROBLEMS, CONTINUATION AND CESSATION OF BREASTFEEDING 
Table VII.1 Reported nursing problems by WIC mothers at the 
time of the Month 1, Month 3 and Month 5 interviews 
153 
Will repeat  
 
Figure VII.1 Percentage of breastfeeding WIC mothers who 
report experiencing nursing problems in Months 1,3 and 5 
154 
Will repeat  
 
Table VII.2 Median age of breastfeeding cessation, age when 
25% and age when 75% of the infants are weaned from the 
breast 
163 
Will not repeat; similar information 
can be better displayed in a graphic 

Appendix A 
Summary of WIC-IFPS-1 Analyses to be Repeated 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-4 
 
Table A-1. 
List of WIC-IFPS-1 report tables and figures (continued) 
 
Table/Figure 
Page 
Status 
Figure VII.3 Percentage of all WIC mothers breastfeeding, by 
age of the infant 
164 
Will repeat  
But infant age will not be in days 
Figure VII.4 Percentage of all WIC mothers still breastfeeding, 
by age of the infant and age of the mother 
165 
Will repeat 
But infant age will not be in days 
Figure VII.5 Percentage of all WIC mothers still breast-
feeding, by age of the infant and whether the mother reports 
knowing about the special WIC food package for breast-
feeding women who do not accept intent formula for WIC 
166 
Will repeat  
But infant age will not be in days 
 
Table VII.3 Relative risks estimated by the multivariate 
models of rates of breastfeeding cessation (survival analysis) 
168 
Will repeat similar content but models 
will differ 
Figure VII.6 Percentage of WIC mothers still breastfeeding by 
age of the infant and reported receipt of none, one, two, or 
three WIC program components that support breastfeeding 
173 
Will repeat  
But infant age will not be in days 
CHAPTER VIII: INITIATION OF SUPPLEMENTAL FOODS: THE TRANSITIONAL PHASE OF INFANT FEEDING 
Figure VIII.1 A model of early initiation of supplemental foods 
and the measures of its predictors from the WIC-IFPS  
180 
Will replace with graphics of updated 
introduction of other foods model 
Figure VIII.2 Percentage of WIC mothers who have not yet 
initiated cereals, vegetables, and meats at each age of the 
infant 
186 
Will repeat  
But infant age will not be in days 
Figure VIII.3 Percentage of WIC mothers who have not yet 
initiated dairy foods, high-protein foods other than meats, and 
sweet/snack foods, at each age of the infant  
188 
Will repeat (food categories may 
differ) 
But infant age will not be in days 
Table VIII.1 Median age of the infant (in days) when specific 
supplemental foods are initiated by selected socio-
demographic characteristics of the mother 
189 
Will repeat  
But infant age will not be in days 
Figure VIII.4 Percentage of WIC mothers who have not yet 
initiated cereals at each age of the infant, by maternal 
immigrant status  
190 
Will repeat  
But infant age will not be in days 
Figure VIII.5 Percentage of mothers initiating cereals, fruits, 
vegetables, and meats as the first, second, third or fourth 
type of supplemental food  
192 
Will repeat  
 
Table VIII.2 Percentage distribution of the order of initiation of 
cereals, fruits, vegetables, and meats, by race/ethnicity of the 
mother 
194 
Will repeat  
 
Table VIII.3 Relative risk of initiating cereals prior to four 
months of age 
196 
Will repeat similar content but models 
will differ 
Table VIII.4 Relative risk of initiating fruits prior to four 
months of age 
199 
Will repeat similar content but models 
will differ 
Table VIII.4 Relative risk of initiating fruits prior to four 
months of age 
201 
Will repeat similar content but models 
will differ  
Figure VIII.6 Percentage of WIC mothers who have not yet 
initiated fruit juices, sweet drinks, and cow milk or other milk 
at each age of infant  
207 
Will repeat  
 
Table VIII.6.Median age of the infant at the time of initiation 
of fruit juices or sweet drinks by selected socio-demographics  
208 
Will repeat 
 
Figure VIII.7 Percentage of WIC mothers who have not yet 
sweet drinks at each age of infant, by race/ethnicity of the 
mother  
209 
Will repeat 
CHAPTER IX SUPPLEMENTAL FOOD FEEDING PRACTICES 

Appendix A 
Summary of WIC-IFPS-1 Analyses to be Repeated 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-5 
 
Table A-1. 
List of WIC-IFPS-1 report tables and figures (continued) 
 
Table/Figure 
Page 
Status 
Table IX.1 WIC-IFPS interview months when questions on the 
method of feeding supplemental foods were elicited 
214 
Will not repeat as we focus on the 
dates changes occurred and not the 
timing of the interview to get 
behavioral changes information  
Table IX.1 Methods of feeding supplemental foods at 
interview months when data was elicited 
215 
Will repeat  
 
Figure IX.1 Percentage of WIC infants receiving supplemental 
foods using a spoon at interview months 2, 4, 5 and 9 by race 
and ethnicity of the mother 
216 
Will repeat  
Figure IX.2 Percentage of WIC mothers who have used an 
infant feeder sometime during infancy by race and ethnicity 
of the mother 
217 
Will repeat  
Table IX.3 Percentage of WIC mothers who adopt 
supplemental food feeding practices that are generally not 
recommended  
218 
Will repeat Rule changes? 
Figure IX.3 Percentage of WIC mothers who feed 
supplemental foods before month 4, prior to using a spoon, 
by race and ethnicity of the mother 
220 
Will repeat 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
A-6 
 
This page left intentionally blank 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-1 
 
Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
Table B-1 shows which analyses answer each research questions and whether the analysis is repeated 
from a past study or new. In cases in which the analyses repeats work from past studies we provide 
the study reference and page number for the relevant table or figure21.  
 
Table B-1. 
Tabular presentation of research design 
 
Research question 
Analysis and format  
Repeated 
or new  
1: What is the participant’s 
practice on breastfeeding 
and formula feeding her 
infant? 
Table: Breastfeeding initiation rates by selected socio-
demographic and health-related characteristics 
(Cumulative, Months 1,3) 
Figure: Breastfeeding initiation rates, by race and ethnicity 
of the mother (Cumulative, Months 1, 3) 
Figure: Percentages of only breastfeeding, combined 
breast-and formula feeding, and only formula-feeding WIC 
mothers at each month of interview (Months 1-13)  
Table: Percentage distribution of the infants by initial diets 
at the at the time of each interview month; by selected 
socio-demographic characteristics (Months 1, 3)  
Table:(Model) Estimates of the relative odds estimated by 
the logistic regression model of breastfeeding initiation 
(Cumulative, Months 1,3)  
Table:(Model) Estimates of the relative risk estimated by 
the multivariate models of rates of formula 
supplementation (survival analysis) (Months 1-13)  
Table. (Model) Relative risks estimated by the multivariate 
models of rates of breastfeeding cessation (survival 
analysis) (Months 1-13) 
Repeated 
from IFPS 
pages53, 
54,88, 90, 
58,96, 
168 
 
 
                                                
21 IFPS refers to Baydar, et al. Final Report: WIC Infant Feeding Practice Study, November 1997.  
 FITSa refers to Seiga-Riz,Anna Marie et al. Food Consumption Patterns of Infants and Toddlers: Where are we Now? in the Supplement to the Journal 
of the American Dietetic Association, 2010. 
 FITSb refers to Devaney, Barabara et al. Nutrient Intakes of Infants and Toddlers in the Supplement to the Journal of the American Dietetic Association, 
2004 
 FITSc refers to Skinner, Jean D. et al. Meal and Snack Patterns of Infants and Toddlers in the Supplement to the Journal of the American Dietetic 
Association, 2004 
 FITSd refers to Ponza, Michael et al. Nutrient Intakes and Food Choices of Infants and Toddlers and Toddlers Participating in WIC in the 
Supplement to the Journal of the American Dietetic Association, 20040 
 FITSe refers to Carruth, Betty Ruthet al. Developmental Milestones and Self-Feeding Behaviors in Infants and Toddlers in the Supplement to the 
Journal of the American Dietetic Association, 20040 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-2 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
1a: Does the practice/behavior 
correspond to specific past 
feeding experiences 
(cultural norms, support 
received, personal feelings, 
barriers encountered, etc.)? 
 Table: Items that constitute the perceived benefits of 
breastfeeding and perceived barriers to breastfeeding 
scales (factor analysis) (Prenatal) 
Table: Percentage of mothers agreeing with statements 
about perceived benefits of breastfeeding by breastfeeding 
decision (Prenatal) 
Table Percentage of mothers agreeing with the statements 
(Prenatal) about perceived barriers to breastfeeding by 
breastfeeding decision 
Table Percentage of mothers receiving breastfeeding 
education/support (WIC vs. elsewhere) by breastfeeding 
decision (Cumulative; Months 1,3) 
Same as breastfeeding initiation model above  
Repeated 
from IFPS 
pages 71, 
73, and 74 
 
Last table 
is new  
 
 
1b: How does breastfeeding 
advice or support compare 
to rates of initiation, 
duration and exclusivity of 
breastfeeding? 
Figure: (Model) Predicted relative odds of initiating 
breastfeeding for WIC mothers who received breastfeeding 
information and advice from different sources (Cumulative; 
Months 1,3) 
 
Same as last table above and formula supplementation 
and breastfeeding cessation models in question 1 
Repeated 
from IFPS, 
page 63 
but use 
different 
categories 
1c: Are differences from one 
re-interview to the next 
statistically significant? 
Figure :Percentages of breastfeeding WIC mothers, by type 
of breastfeeding practice at each month of interview 
(Month 1-9) 
Figure: Percentage of breastfeeding WIC mothers who have 
not yet initiated formula, by the age of the infant (Months 
1-9) 
Repeated 
from IFPS, 
pages 92 
and 94 
2: What is the frequency of 
breastfeeding or formula 
feedings and foods (total 
and by breast, formula, 
combinations, and foods) 
given?  
Table : Usual number of daily breastfeeds, by selected 
maternal socio-demographic characteristics (Months 1, 3, 
5) 
Table: Usual number of formula or combination feedings, 
by selected maternal socio-demographic characteristics 
(Months 1, 3, 5) 
Table: Usual number of solid food feedings , by selected 
maternal socio-demographic characteristics (Months 1, 3, 
5) 
Repeated 
from IFPS, 
pages 131 
 
2nd and 
3rd tables 
are new 
2a: Do mothers/caregivers ever 
put anything other than 
human milk or formula in a 
bottle that is fed to their 
infant? 
Table: Percentage of WIC mothers who add other foods or 
liquids into the bottle with the formula by selected socio-
demographic characteristics (Months 1,3) 
Figure: Percentage of mothers who report adding other 
foods or liquids in the bottle with formula at months 3 
(Month 3)  
Figure: Percentage of mothers who report adding other 
foods in the bottle with formula at Month 1 among those 
who think that the amount of formula given by WIC is more 
than enough, the right amount, or not enough (Month 1) 
Repeated 
from IFPS, 
pages 
141, 142, 
143 
3: What is the mean and 
range in the incidence, 
duration, and intensity of 
breastfeeding? 
Not collecting duration of 
individual breastfeeds 
Table: Mean and standard deviation in the number of 
breastfeeds and intensity (% of feedings that are breast 
feedings) per day by month (Months 1-7) 
New 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-3 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
3a: Are differences from one 
re-interview to another 
statistically significant? 
Same as above 
Same as 
above 
4: What are the breastfeeding 
history characteristics of 
postpartum women by level 
(e.g., quintile) of mean 
incidence, duration, and 
intensity? 
Table: Median age in weeks/days of the infant at the time 
when formula supplementation is initiated, by selected 
socio-demographic characteristics and previous 
breastfeeding experience (Cumulative; Months 1-13) 
Table: Breastfeeding frequency, intensity, and duration by 
initial breastfeeding status (breastfeed only or with 
formula) (Months 1-7) 
Repeated 
from IFPS, 
pages 94 
 
2nd table 
is new 
4a: Do these characteristics 
change from one interview 
to the next? If so, are the 
differences statistically 
significant? 
Same as second table above 
New 
5: How does the mother/ 
caregiver determine the 
daily feeding schedule for 
the infant? 
Table: Breastfeeding schedules of WIC mothers over the 
first five months of their infants’ first year (Months 1,3, 5) 
Figure: Percentage of WIC mothers who breastfeed on a 
set schedule, when the infant cries or seems hungry, and 
on a mixed schedule (Months 1-13) 
Repeated 
from IFPS-
1, pages 
128, 130 
 
5a: How does this vary by day 
of the week, work schedule, 
and other factors? 
Not collecting day of but rather 
typical pattern week 
Table: Breastfeeding schedules of WIC mothers over the 
first 13 months of their infants’ first year by mother’s work 
status and child care status (Months 1-13) 
New 
6: What are the feeding 
practices with pumping or 
expressing human milk? 
Table: Percentage of WIC mothers who report expressing 
milk during the past week by selected maternal socio-
demographics (Months 1-7) 
Figure: Percentage of breastfeeding WIC mothers 
expressing milk, using electric breast pumps, using manual 
breast pumps, and expressing milk by hand (Cumulative; 
Months 1-7) 
Repeated 
from IFPS-
1, pages 
132, 133 
with added 
months 
6a: How does the mother/ 
caregiver determine these 
practices? 
Table: Percentage distribution of reason for pumping 
(Cumulative; Months 1-7) 
New 
6b: How does this vary by day 
of the week, work schedule, 
healthcare support and 
other factors? 
Not collecting day of week 
Table: Percentage of breastfeeding WIC mothers 
expressing milk, using electric breast pumps, using manual 
breast pumps, and expressing milk by hand by work status 
and receipt of WIC support services (Months 1-7) 
New 
7: How does the mother/ 
caregiver determine the 
specific time and duration 
of feeding? 
Same table and figure as for question 5 
Same as 
for 
question 5 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-4 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
8: 
What are mothers 
reported breastfeeding 
problems? 
Table: Reported breastfeeding problems by WIC mothers at 
the time of the month 1, month 3 and month 5 interviews 
(list of problems) (Months 1, 3, 5) 
Figure: Percentage of breastfeeding WIC mothers who 
report experiencing breastfeeding problems in months 1, 3 
and 5 (main types of problems) (Months 1,3,5) 
Repeated 
from IFPS-
1, pages 
153, 154 
expanded 
to include 
environ-
mental 
barriers 
8a: Among those who had 
common breastfeeding 
problems, what are the 
number and percent 
receiving help from the 
WIC staff? 
Table: Percentage of mothers reporting breastfeeding 
problems who received help by source of support 
(Cumulative; Months 1,3,5)  
New 
9: 
What is the distribution of 
caregiver understanding of 
appropriate feeding 
behaviors associated with 
infants’ non verbal cues 
regarding satiety gestures 
and cry interpretations? 
Table: Percentage of caregivers who respond to different 
infants cues with appropriate understanding (Month 3) 
New 
10: How are caregivers 
obtaining or preparing 
baby foods (e.g., making at 
home, buying, getting from 
WIC, etc.)? 
Table: Percentage distribution of the sources for baby foods 
(Months 7-13) 
Table: Share of purchased baby food covered by WIC 
vouchers (Months 7-13) 
New 
11: How do caregivers’ infant 
food choices vary across 
feedings (e.g., only human 
milk, only formula, 
mixture, alterations, or 
other drinks)? 
Table: Percentage distribution of food choices across 
feedings (morning, afternoon, evening) (Months 1-13) 
New 
11a: Is the caregiver 
supplementing with food 
and/or other beverages 
besides formula and 
breast milk (e.g., soda, tea, 
juice)? 
Table: Percentage of infants and toddlers consuming 
different types of milk and other beverages by age (Months 
3-24) 
Table : Median age of the infant (in weeks/days) when 
specific supplemental foods are initiated by selected socio-
demographic characteristics of the mother (Months 1-24) 
Table: Percentage of infants and toddlers consuming 
grains, vegetables, fruits, and meats/other protein sources, 
and desserts, sweets, sweetened beverages and salty 
snacks by age (Months 3-24) 
Repeated 
from 
FITSa, 
page S40 
with other 
beverages 
added and 
IFPS, page 
189 with 
months 
added 
 
3rd table 
is new 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-5 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
11b: What is the percentage of 
combination feedings 
comparing human milk, 
formula, and/or foods 
(e.g., mom supplements in 
the evening to allow infant 
to sleep through the night 
being 90% human milk, 
5% baby foods, and 5% 
formula per day)? 
Table: Percentage distribution of combinations feedings by 
age (Months 1-13) 
 
New 
11c: How much food and/or 
cow’s milk (i.e., whole, 2%, 
chocolate or 1% milk) is 
used? 
Same tables as in question 11a 
Same as 
for 
question 
11a 
12: What WIC Food Package is 
the caregiver/infant 
receiving (i.e., full 
breastfeeding or partial 
breastfeeding)? 
Table: Percentage of caregivers and infants by type of food 
package received (Months 1, 7, 13) 
New 
13: What are the barriers 
(e.g., environmental) in 
breastfeeding practices 
and behaviors for infants?  
Same tables as in question 8 
Same as 
in question 
8 
13a: For those who identified 
barriers, what do they 
think would be the best 
possible solution to 
overcome the barriers? 
Table: Percentage distribution of possible solutions to 
barriers (Cumulative; Months 1,3, 5) 
New 
14: What do 
mothers/caregivers 
perceive to be the impact 
of their food package 
choices on their 
breastfeeding behavior? 
Table: Percentage distribution of the perceived impact of 
food package choices on the breastfeeding decision 
(Months 3, 7)  
New 
15: What do 
mothers/caregivers 
perceive to be the impact 
of their food package 
choices on the food their 
child receives? 
Table: Percentage distribution of the impacts of food 
package choice on food child receives (Months 7, 15) 
New 
16: What is the nutrient intake 
of infants and (if option 
funded) toddlers? 
Table: Usual nutrient intake distributions of infants: 
Micronutrients (Months 3,5 and 7-11)  
Table: Usual nutrient intake distributions of toddlers 
(Months 13 to 24) 
Table: Usual nutrient intake distributions of infants: 
Macronutrients (Months 5-24) 
Repeated 
from 
FITSb, 
page S16, 
S17, and 
S18 
16a: How does the nutrient 
intake vary by State food 
package choices? 
Table: Estimates of the effect behaviors and demographics 
have on nutrient intake(Months 7, 13, 24) 
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-6 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
16b: How does the nutrient 
intake vary by age, primary 
milk source, and other 
factors? 
Same table as above 
Same as 
above 
17: What is the frequency and 
nature of mothers’ 
reported breastfeeding 
problems? 
Same table as for question 8 
Same as 
for 
question 8 
17a: Did the mother receive 
support? For whom? If not, 
from whom would she 
have liked support (WIC, 
family, all the above, etc.)? 
Same table as for question 8a 
Same as 
for 
question 
8a 
17b: Are there group 
differences in the 
prevalence of 
breastfeeding problems by 
race/ethnicity, age, and 
education of the mother? 
Table: Percentages of mothers reporting breastfeeding 
problems in the first 5 months by type of problem and 
socio-demographics (Cumulative; Months 1,3,5) 
New 
17c: How does the frequency of 
breastfeeding problems 
vary with other actors? 
Same table as above 
Same as 
above 
17d: What are the resolutions 
of the problems? 
Table: Percentage distribution of resolutions by type of 
breastfeeding problem (Cumulative; Months 1,3,5) 
New 
18: At each age, what 
percentages of WIC infants 
and/or toddlers use a cup 
(with and without 
assistance), a spoon, a 
Sippy cup or a pacifier 
throughout the first years 
of life? What percentage 
of WIC infants self-feed 
during mealtimes? How 
does this vary by eating 
location (e.g., home, 
childcare, away from 
home with primary 
caretaker)?  
Not collecting by location 
Table: Self feeding skills and the percentage of toddlers 
who were reported to show the self feeding skill by age 
(Months 9, 11, 13, 18) 
Table. Methods of feeding supplemental foods at interview 
months when data was elicited (Months 3-9, 13, 18) 
Figure Percentage of WIC infants receiving supplemental 
foods using a spoon by race and ethnicity of the mother 
(Months 3-9, 13, 18) 
 
Repeated 
from 
FITSe, 
page s53 
and IFPS, 
page 215 
and 216 
 
3rd table 
in new 
19: How well are caregivers 
who use formula following 
the standard or specialized 
formula dilutions 
prescribed by the doctor or 
nutritionist? What is the 
prescribed amount and is 
this over or under stand 
recommendations? 
Table: Percentage of caregivers who deviate from formula 
dilution directions by type of deviation (Cumulative; Months 
3, 7, 11) 
Table: Percentage if caregivers receiving doctor or 
nutritionist dilution guidance that deviate from 
recommendations by type of deviation (Cumulative; Months 
1-13) 
 
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-7 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
20: What is the frequency of 
methods used by the 
caregiver to prepare foods 
(such as pureeing or 
mashing with utensils or 
by chewing up foods then 
giving to child)? 
Table: Percentage distribution of food preparation methods 
used by caregivers (Months 7, 9, 11, 13) 
New 
21: When is pumping or 
expressing human milk 
done and how often? What 
are the storage practices? 
If using a breast pump 
where did mother receive 
the pump from? What is 
the distribution of the 
frequency of use of 
pumps? 
Table: The average number of times a day women pump or 
express milk among those doing this (Months 1-13) 
Table: Percentage distribution of pumping/ expressing milk 
by location, time of day, and storage practices (Months 1-
13) 
Table: Percentage distribution of sources for pumps 
(Cumulative; Months 1,3) 
 
Same table for question 6  
New and 
same as 
for 
question 6 
22: What non-program and 
program factors (i.e., 
supplies, policies, staff 
competencies, and 
actions) contribute to the 
likelihood of initiating 
breastfeeding, formula 
supplementation, baby 
foods, and cereals? 
Same tables on breastfeeding decision and formula 
supplementation model estimates as for question 1 
Table (Model) Relative risk of initiating cereals prior to four 
and six months of age (Cumulative; Months 1-13) 
Table: (Model) Relative risk of initiating fruits prior to four 
and six months of age (Cumulative; Months 1-13 
Table: (Model) Relative risk of initiating vegetables prior to 
four and six months of age (Cumulative; Months 1-13) 
Repeated 
from  
IFPS, 
pages 
196,199, 
and 201 
23: For women who chose a 
fully breastfeeding 
package yet also use 
formula, where do these 
women obtain formula? 
Table: Percentage distribution of formula sources for 
women choosing the breastfeeding package(Cumulative; 
Months 1-13) 
 
New 
24: If formula is used, what 
type(s) of formula (i.e., 
exempt, soy, milk-based, 
ready to drink powdered or 
concentrated)? 
Table: Percentage distribution of formula types 
(Cumulative; Months 1-13) 
 
New 
24a: Who provided formula? 
Table: Percentage distribution of formula sources 
(Cumulative; Months 1-13) 
New  
24b: What was the reason for 
the formula? 
Table: Percentage distribution of reasons for using formula 
by infant age (Months 1-13) 
New 
24c: How do these factors 
change in relation to the 
age of the infant? 
Same as above  
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-8 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
25: Does the mother or child 
have any medical 
conditions? If so, what 
were the actions taken to 
rectify? 
Are only asking about 
treatments that could affect 
feeding behaviors (e.g., 
hospitalization, medication, 
etc.)  
Table: Percentage of mothers with health problems during 
pregnancy and after birth by main treatment (Month 1) 
Table Percentage of children with health problems by main 
treatment (Month 1) 
New 
26: If child ever used a pacifier 
when was it introduced 
and who introduced it? For 
what reason was the 
pacifier introduced? How 
often is the pacifier used 
and are there specific 
times when it is used or 
not used? 
Not asking when pacifier was 
introduced or frequency of use 
or times used as it is unlikely to 
provide useful information 
Table: Percentage of children using pacifiers and timing of 
introduction (Month 3) 
Table: Percentage distribution of pacifier use by reason 
(Month 3) 
New 
27: What is the overall 
prevalence of 
breastfeeding problems 
over the first half of 
infancy? What is the 
distribution of type of 
problem? How does this 
change over time? 
Same as tables for question 8 and 17b 
 
Same as 
for 
question 8 
and 17b 
28: How do the feeding 
practices of infants and 
children who continue WIC 
participation compare to 
those who leave the 
program or have non-
continuous periods of 
participation? 
Same tables as for question 22 
Same as 
for 
question 
22 
29: What is the first feeding of 
WIC infants in the 
hospital? 
Table: The first feeding received by WIC infants in the 
hospital (Month 1) 
Figure: The first feeding of WIC infants in the hospital, by 
race and ethnicity of the mother(Month 1) 
 
Repeated 
from  
IFPS, page 
110 , 111 
29a: Was the mother 
encouraged to initiate 
breastfeeding? 
Table: Percentage of mothers encouraged to breastfeed by 
family, WIC staff, or provider (Month 1) 
 
New 
29b: Did mother initiate 
breastfeeding in the 
hospital? 
Table: Percentages of mothers who initiated breastfeeding 
in the hospital by time after birth (Month 1) 
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-9 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
29c: If so, how long after 
delivery was feeding 
initiated/ encouraged 
(such as within the first 
hour after birth)? 
Same as above 
New 
29d: Did the infant receive 
anything other than 
human milk in the 
hospital? If so, what, when 
and how often? 
Table: Percentage of infants who received something other 
than human milk in the hospital by product, day, and 
frequency (Month 1) 
 
New 
30: What are mothers’ 
reported breastfeeding 
problems while in the 
hospital? Among those 
who had common 
breastfeeding problems, 
what are the number and 
percent receiving help 
from the hospital staff? 
Table: Percentages of mothers reporting nursing problems 
while in the hospital (Month 1) 
 
Figure: Percentage of WIC mothers who did not receive 
help from the hospital staff among those who had common 
nursing problems (Month 1) 
 
Repeated 
from  
IFPS, page 
113 , 114 
31: Did the mother/caregiver 
report receiving various 
items such as formula, 
pacifiers, bottles, breast 
pump; perhaps as part of a 
give package from inside 
the hospital? What is the 
distribution of the content 
of these items? How does 
this relate to breastfeeding 
and other infant feeding 
practices? 
Figure: Percentage of WIC mothers who reported receiving 
various items in their gift packages from the hospital 
(Month 1) 
 
Table: Estimates of the relative odds of breastfeeding at 
hospital discharge (Month 1) 
 
Same tables on breastfeeding decision and formula 
supplementation model estimates and introduction of 
other foods (cereal) model as in question 22 
Repeated 
from IFPS, 
page 115 
2nd table 
is new 
 
Remaining 
tables are 
same as 
question 
22 
32: Did the mother use any of 
the following services in 
the hospital: Media 
campaign materials, 
Lactation consultant, 
Other trained specialist, 
Breastfeeding support 
groups or classes, 
Equipment for 
breastfeeding support, 
Peer counseling, Other 
counseling, 24-hr 
breastfeeding hotline, 
Designated staff members 
contact, Any other 
activities 
Table: Percentage of WIC mothers who reported receiving 
various services from the hospital (infant in room, feeding 
on demand, referral for breastfeeding support, etc.)(Month 
1) 
 
 
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-10 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
33: Did the mother birth 
multiples? If yes – 
vaginally or cesarean 
section? 
Table: Percentage of multiple births and type of delivery 
(Month 1) 
 
New 
33a: Infants health status (such 
as height, weight, head 
circumference, blood tests; 
Apgar scoring, 
immunizations, amount of 
wet/soiled diapers, and 
food allergy)?  
Not collecting data on food 
allergies 
Table: Percentage distribution of infants’ health 
characteristics (Month 1) 
 
New 
34: When was mother 
discharged from hospital? 
Infant? How do these 
relate to infant feeding at 
discharge and later? 
Figure : Number of days of hospital stay for WIC mothers 
and infants (Month 1) 
Table: Relative odds of formula feeding at hospital 
discharge for WIC mothers who breastfeed at the first 
feeding (Month 1) 
Table: Relative odds of breastfeeding at hospital discharge 
for WIC mothers who formula feed at the first feeding 
(Month 1) 
Same as second table for question 31 and last table for 
question 1 
IFPS 
pages 
109, 118, 
and 120  
35: What was the type(s) of 
feeding at hospital 
discharge (e.g., breast, 
formula, or both)? 
Table: Percentage of type of feeding at hospital discharge 
by type of first feeding (Month 1) 
 
IFPS page 
116 
36: If applicable, what is the 
amount of expressed milk 
during the 1st 2 weeks 
after birth? What was 
done with the expressed 
milk? 
Interview occurs at 1 month 
and not at 2 weeks 
Table: Average amount of expressed milk for breastfeeding 
mothers at 1 month in past 24 hours (Month 1) 
 
Table: Percentage distribution of what was done with the 
expressed milk (Month 1) 
 
New 
 
37: What are the reasons why 
mothers stop 
breastfeeding during the 
first few weeks of their 
infants’ life? How often do 
these occur? Which pose 
the greatest risk to 
breastfeeding success and 
duration? 
Table: Frequency of top 10 reasons women stop breast 
feeding within the first 2 and 6 weeks (Cumulative; Months 
1,3) 
 
Same as breastfeeding cessation model in question 1 
New 
 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-11 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated 
or new  
38: What factors play into a 
mother being successful at 
breastfeeding her infant 
during the first few weeks 
of life and 4-6 months of 
life? What factors are 
associated with successful 
breastfeeding for the first 
6 months of her infant’s 
life? 
Table: Characteristics and circumstances of mothers 
breastfeeding (Months 1, 3, 6) 
 
Same as breastfeeding initiation and cessation models in 
question 1 
New 
 
 
39: What is the distribution of 
reasons for mothers 
coming into WIC clinics at 
4-6 month and in some 
cases stopping 
breastfeeding? 
Table: Percentage distribution of reasons for stopping 
breastfeeding between 2-3 and4-6 months 
 
New 
40: What is the mothers 
Edinburgh Postpartum 
Depression Scale score? 
How does this relate to 
infant feeding practices? 
Table: Average Edinburgh Postpartum Depression Scale 
score by breastfeeding status (Months 3 , 6) 
 
Same as the last 2 model tables for question 1 
New and 
same as 
the last 2 
model 
tables for 
question 1 
41: How do the answers to all 
above listed research 
questions vary in relation 
to the infant’s health 
status at birth (such as 
length, weight, etc.) and 
household demographic 
characteristics? 
Table: Frequency of top 5 reasons women stop breast 
feeding within the first 6 weeks by infant health status and 
household demographics (Cumulative; Months 1,3) 
 
Same as breastfeeding decision and duration model tables 
for question 1 
 
Same as breastfeeding cessation model table for question 
37 
New 
 
 
Same as 
for 
question 1 
and 37 
42: For working mothers, 
describe the distribution of 
characteristics of the place 
at work to pump human 
milk? Does the mother’s 
employer have a workplace 
lactation program or 
provide any workplace 
accommodations (such as 
reasonable breaks, an 
appropriate place to store 
milk, a place other than the 
bathroom to pump/express 
human milk, etc.)? 
Table: Percentage distribution of the accommodations 
available at work to assist with pumping milk (Month 3) 
New 
 
 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-12 
 
 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated or 
new  
43: Is the respondent’s child 
participating in the CACFP? 
If yes, what is the transition 
of baby foods, table foods, 
cow’s milk, and human 
milk in the CACFP and 
other facilities? 
Table: Percentage distribution of children in childcare by 
type of childcare (Months 3,7,13,24) 
Table: Within CACFP facilities, the average month of key 
food transitions (Cumulative; Months 7,13) 
New 
44: If applicable, when did the 
child go into a childcare 
facility and what kind (i.e., 
child care center, family 
day care homes, early head 
start, homeless shelters, 
etc.)? 
Same as table above 
Table: Average age of child when they first started 
childcare by type of childcare (Cumulative; Months 3, 7, 13, 
24) 
New 
45: For infants in child care: 
What are the general 
barriers to breastfeeding in 
these facilities? Who 
provides the food to these 
facilities? Is human milk 
given by bottle or nipple 
when at facilities (e.g., may 
go to facility on break to 
breastfeed or some 
mothers only bottle feed 
human milk to infants)? If 
the mother providing 
expressed human milk or 
breastfeeding the infant at 
the facility? How does 
breastfeeding success 
relate to childcare policies 
and practices? 
Table: Frequency of top 10 barriers to breastfeeding 
children in childcare (Cumulative; Months 3,7) 
Table: Percentage distribution of who provides the food for 
the child by type of childcare (Months 3, 7, 13, 24) 
Table: Percentage of mothers with children in childcare 
who go to facility to breastfeed during the day (Cumulative; 
Months 3,7) 
Table: Percentage of children in childcare getting human 
milk by age of infant and method of receipt (Months 3,7) 
New 
46: What are the caregivers 
socio-demographic 
characteristics (i.e., sex, 
birth order, age of mother 
at time of birth, US citizen, 
marital status, household 
size, poverty level, receipt 
of public assistance, 
education, employment 
prior WIC, drug history, 
healthcare, Medicaid, etc.) 
by maternal race and 
ethnicity? What is the 
Native language? 
Not including drug history or 
native language. Will use 
Table: Percentage distribution of socio-demographic 
characteristics by maternal/caregiver race and ethnicity 
(Baseline) 
Repeated 
from IFPS, 
page 25 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-13 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated or 
new  
foreign born rather than 
citizenship. 
47: What are the distributions 
of caregivers and 
participants health-related 
characteristics by race and 
ethnicity of the mother? 
Table: Percentage distribution of reported health-related 
characteristics by maternal race and ethnicity of the 
mother (month 1) 
Repeated 
from IFPS-1, 
page 26 
48: Is this the mother’s first 
time breastfeeding or 
formula feeding? 
Table: Percentage of WIC mothers by previous feeding 
practice experiences for siblings (Baseline) 
 
New 
49: Did the mother breastfeed 
siblings? 
Same as above 
New 
49a: If so, when did she initiate 
and how long did she 
breastfeed? 
Table: Average longest duration and number of years ago 
of previous breastfeeding experience (Baseline) 
New 
49b: When did she first give 
baby foods and table 
foods to siblings on WIC? 
Table: Average infants age mother previously introduced 
solid foods (cereal and other table by type of food)to 
siblings(Baseline) 
New 
50: When did the 
mother/caregiver start 
participating in the WIC 
program? 
Table: Percentage of mothers/caregivers who have 
previously participated in WIC and by the length of 
participation (Baseline) 
Table: For current child, percentage distribution of when 
the mother/caregiver joined WIC by infants age (screener)  
New 
51: What are mothers’ 
influences to breastfeed or 
formula feed? What 
influences the mother to 
breastfeed or formula 
feed? 
Same as model estimate tables for question 1a 
Same as for 
question 1a 
52: Does the mother intend to 
breastfeed? 
Table: Mothers’ intention to breastfeed by socio-
demographics (Prenatal) 
New 
53: Did the mother receive 
counseling on infant 
feeding and care and by 
whom? 
Table: Percentages of mothers reporting receipt of 
information about various aspects of infant feeding from 
WIC(Month 1) 
Table: Percentages of mothers reporting receipt of 
information about infant feeding from other professional 
sources (Month 1) 
Repeated 
from IFPS, 
page 28and 
new with the 
addition of 
non-WIC 
sources of 
information 
53a: Where did the mother 
receive her counseling on 
infant feeding and care 
(e.g., clinical dietitian from 
hospital, nurse practitioner 
or WIC nutritionist clinic)? 
Same as above 
Same as 
above 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-14 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated or 
new  
54: What are staff and 
mothers/caregivers 
knowledge, attitudes, and 
beliefs about nutrition and 
behavior (e.g., following a 
kosher, vegan diet or other 
religious views affecting 
food consumption, etc.) for 
infants and toddlers? 
Table: Percentage of mothers having certain knowledge 
and attitudes about nutrition and behavior (Month 13) 
Table: Percentage of WIC staff having certain knowledge 
and attitudes about infant and toddler nutrition (WIC staff 
survey) 
New 
55: What are the 
mothers/caregivers 
challenges in nutrition 
education involving feeding 
practices? 
Table: Percentage of Top 5 nutrition challenges for 
mothers/caregivers reporting challenges getting nutrition 
information by source(Months 5, 15) 
New 
56: Where does the 
mother/caregiver get 
nutrition information (e.g., 
WIC, websites, social 
media, family, friends, 
social networks, healthcare 
providers, etc.)? 
Table: Percentage distribution of mothers/caregivers 
sources of nutrition information (Months 5, 15) 
New 
57: What triggers 
mothers/caregivers 
behavior to get information 
(such as infant won’t stop 
crying, desire to be good 
mother, etc.)? 
Table: Triggers for seeking nutrition information (Months 5, 
15) 
New 
58: What are the physicians’ 
views and/or beliefs 
regarding breastfeeding a 
preemie vs. non-preemie 
(e.g., growth)?  
Not interviewing providers. 
Instead asking 
mother/caregiver their 
perception of their provider’s 
views 
Table: Percentage distribution of mother’s perception of 
physician’s views about breastfeeding preemies (Month 1) 
New 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-15 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated or 
new  
59: What is the relationship of 
infant and child feeding 
practices to infant and 
child growth and weight 
status (e.g., overweight/ 
underweight)? 
Table: Percentage of children in each weight/length 
quintile at 6, 12 and 24 months by breastfeeding 
experience (Months 1, 3 and clinical records for 6, 12, 24) 
Table: Percentage of children in each weight/length 
quintile at 6, 12 and 24 months by timing of the 
introduction of different types of solid foods (Months 1-13 
and clinical records for 24) 
Table. Percentage of children in top 20% and bottom 20% 
of the weight/length distribution at 12 and 24 months by 
breastfeeding experience and socio-demographics (Months 
1, 3 and clinical records 12, 24) 
Table: Average child weight/length gain in first 6 months 
by breastfeeding experience (Months 1 ,3 and clinical 
records for 1, 5) 
Table: Average child weight/length gain between 6-12 
months by breastfeeding experience (Months 1, 3 and 
clinical records for 6, 12)  
Table. (Model) OLS regression estimates of the impact of 
the impact of socio- demographics and feeding practices 
on weight/length at 24 month (Cumulative; Months 1-24 
and clinical records for 6, 12 24) 
Table: (Model) Quantile regression estimates of the impact 
of socio- demographics and feeding practices on 
weight/length at 6 month (Cumulative; Months 1-6 and 
clinical records for 6) 
Table: (Model) Quantile regression estimates of the impact 
of socio- demographics and feeding practices on 
weight/length at 12 month (Cumulative; Months 1-13 and 
clinical records for 6, 12) 
Table: (Model) Quantile regression estimates of the impact 
of socio- demographics and feeding practices on 
weight/length at 24 month (Cumulative; Months 1-24 and 
clinical records for 6, 12 24) 
Table: (Model) Growth model estimates of the impact of 
socio- demographics and maternal health on weight gain 
trajectory of the child from birth to 2years (Cumulative; 
Months 1-24 and clinical records for 0, 6, 12 24) 
New 

Appendix B 
Proposed Analyses for Answering 
Each Research Question 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
B-16 
 
Table B-1. 
Tabular presentation of research design (continued) 
 
Research question 
Analysis and format  
Repeated or 
new  
60: What are the 
mothers/caregivers and 
child’s health care 
providers (OBGYN, 
pediatrician, etc.) views or 
beliefs regarding 
breastfeeding? What 
recommendations have 
mothers/caregivers 
received from their health 
care providers regarding 
breastfeeding? 
Not interviewing providers 
Instead asking 
mother/caregiver their 
perception of their provider’s 
views. As such perception of 
views and recommendations 
merge. 
Same as table for 1a 
 
Table: Percentage distribution of mother’s perception of 
physician’s views about breastfeeding (Month 1) 
Same as 
table 1a 
 
2nd table is 
new 
 

 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
C-1 
 
Appendix C 
Example Tables by Socio-Demographics 
 
In this appendix we provide a few examples of how the tables will examine the measures of interest 
vary by key subpopulation groups. 
 
 
TABLE EXAMPLE # 1 
Table C-1 is an example of a new table that does not repeat work from a past study. The outcome 
measure is relatively simple and global in nature and therefore lends itself to making many subgroup 
comparisons. Below are the subgroups comparison we believe may prove meaningful for this 
measure. 
 
Table C-1. 
Mother’s Intention to breastfeed by socio-demographics 
 
 
Intend to breastfeed? 
Total 
Subgroup 
Yes 
No  
Undecided 
n 
Weighted n 
Race* 
 
 
 
 
 
African American 
% 
% 
% 
 
 
White 
 
 
 
 
 
All other 
 
 
 
 
 
Ethnicity* 
 
 
 
 
 
Hispanic 
 
 
 
 
 
Non-Hispanic 
 
 
 
 
 
Breastfeeding experience 
 
 
 
 
 
Never breastfed 
 
 
 
 
 
Breast fed  
 
 
 
 
 
WIC exposure 
 
 
 
 
 
Began prenatally in 1st trimester 
 
 
 
 
 
Began 
prenatally 
after 
1st 
trimester 
 
 
 
 
 
Began postnatally 
 
 
 
 
 
Mother’s weight status 
 
 
 
 
 
Overweight 
 
 
 
 
 
Obese 
 
 
 
 
 
Neither obese or overweight 
 
 
 
 
 
 
 
 

Appendix C 
Example Tables of Socio-Demographics 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
C-2 
 
Table C-1. 
Mother’s Intention to breastfeed by socio-demographics (continued) 
 
 
Intend to breastfeed? 
Total 
Subgroup 
Yes 
No  
Undecided 
n 
Weighted n 
Poverty level 
 
 
 
 
 
0-75% 
% 
% 
% 
 
 
76-130% 
 
 
 
 
 
>130% 
 
 
 
 
 
Mother’s age 
 
 
 
 
 
<20 
 
 
 
 
 
20-25 
 
 
 
 
 
>25 
 
 
 
 
 
Marital status 
 
 
 
 
 
Married 
 
 
 
 
 
Not married 
 
 
 
 
 
Household food security 
 
 
 
 
 
Secure 
 
 
 
 
 
Not secure 
 
 
 
 
 
Total 
 
 
 
 
 
n 
 
 
 
 
 
Weighted n 
 
 
 
 
 
* Chi-square testing subgroup differences is significant at p ≤ .05 
**Chi-square testing subgroup differences is significant at p ≤ .01 
 
 
TABLE EXAMPLE # 2 
Table C-2 is an example of a table that we are repeating from the IFPS-1 study. The first table below 
is a direct replication if the table as it appears in the IFPS-1 study. It includes two subgroup 
comparisons- race/ethnicity and breastfeeding status. 
 
 
 

Appendix C 
Example Tables of Socio-Demographics 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
C-3 
 
Table C-2. 
Percentage of mothers agreeing with statements about perceived benefits of 
breastfeeding by other background characteristics (repeats IFPS-I p 73) 
 
Maternal 
attitude and 
belief 
Race/ethnicity 
Breastfeeding status 
Total 
White  
African 
American 
Hispanic 
Other 
Initiated 
breastfeeding  
Did not 
breastfeed 
n 
Weighted n 
Statement 1* 
% 
% 
% 
% 
% 
% 
 
 
Statement 2@ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
… 
 
 
 
 
 
 
 
 
Statement n 
 
 
 
 
 
 
 
 
Total 
 
 
 
 
 
 
 
 
n 
 
 
 
 
 
 
 
 
Weighted n 
 
 
 
 
 
 
 
 
* Chi-square testing race/ethnicity differences is significant at p ≤ .05 
**Chi-square testing race/ethnicity differences is significant at p ≤ .01 
@ Chi-square testing breastfeeding status differences is significant at p ≤ .05,  
@@ Chi-square testing breastfeeding status differences is significant at p ≤ .01 
Etc. 
 
We believe that it may prove meaningful to look at these responses by mothers’ previous 
breastfeeding experience, marital status, and age as well as show a table shell (Tables C-3) for these 
subgroups below. 
 
 
Table C-3. 
Percentage of mothers agreeing with statements about perceived benefits of 
breastfeeding by breastfeeding group  
 
Maternal 
attitude and 
belief 
Breastfeeding group 
Marital status 
Mother’s age 
Total 
Never 
breastfed 
Breastfed 
Married 
Not married 
<20 
20-
25 
>25 
n 
Weighted n 
Statement 1* 
% 
% 
% 
% 
% 
% 
% 
 
 
Statement 2@ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
… 
 
 
 
 
 
 
 
 
 
Statement n 
 
 
 
 
 
 
 
 
 
Total  
 
 
 
 
 
 
 
 
 
n 
 
 
 
 
 
 
 
 
 
Weighted n 
 
 
 
 
 
 
 
 
 
* Chi-square testing breastfeeding group differences is significant at p ≤ .05,  
**Chi-square testing breastfeeding group differences is significant at p ≤ .01,  
@Chi-square testing marital status differences is significant at p ≤ .05 
@@Chi-square testing marital status differences is significant at p ≤ .05 
Etc. 
 

Appendix C 
Example Tables of Socio-Demographics 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
C-4 
 
TABLE EXAMPLE #3 
Table C-4 is an example of a new table. The outcome measure is triggers mothers have for seeking 
nutrition information which does not lend itself to a single summary measure. Instead, we provide 
the percentage of women who agree with a list of potential triggers. We ask this question when the 
child is 5 months old and beginning to transition to solids as mothers are likely to be seeking 
nutrition information at this time. We repeat this question during the toddler period when the child 
is 15 months as we expect the triggers may change with older children. 
 
Table C-4. 
Triggers for seeking nutrition information 
 
Trigger 
Percentages reporting trigger 
At 5 months 
At 15 months  
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
 
Although unlikely to vary greatly between subpopulations, we believe it may prove meaningful to 
look at these responses by race/ethnicity and mothers’ age and show table shells (Tables C-5 and C-
6) for these subgroups below. 
 
Table C-5. 
Triggers for seeking nutrition information by race/ethnicity 
 
Trigger 
Percentages reporting trigger 
At 5 months 
At 15 months  
White 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
African American 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
Other 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 

Appendix C 
Example Tables of Socio-Demographics 
 
WIC ITFPS-2 Final Research & Analysis Plan 
Deliverable 7b 
C-5 
 
Trigger 
Percentages reporting trigger 
At 5 months 
At 15 months  
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
Hispanic 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
Non-Hispanic 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
 
Table C-6. 
Triggers for seeking nutrition information by mother’s age 
 
Nutrition trigger 
Percentages reporting trigger 
At 5 months 
At 15 months 
< 20 year old 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
20-25 years old 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n 
 
 
¾> 25 years old 
Trigger 1 
% 
% 
Trigger 2 
 
 
Trigger 3 
 
 
Trigger 4 
 
 
Total 
 
 
n 
 
 
Weighted n