U.S. Department of Education

Institute of Education Sciences

NCES 2005–036

Children Born in 2001

First Results From the

Base Year of the Early

Childhood Longitudinal

Study, Birth Cohort (ECLS–B)

Birth Cohort E.D. TAB
U.S. Department of Education

Institute of Education Sciences

NCES 2005–036

Children Born in 2001

First Results From the Base

Year of the Early Childhood

Longitudinal Study, Birth

Cohort (ECLS–B)

E.D. TAB

November 2004

Kristin Denton Flanagan

Education Statistics Services Institute

Jerry West

National Center for

Education Statistics
U.S. Department of Education

Rod Paige

Secretary

Institute of Education Sciences

Grover J. Whitehurst

Director

National Center for Education Statistics

Robert Lerner

Commissioner

The National Center for Education Statistics (NCES) is the primary federal entity for collecting, analyzing, and reporting

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NCES activities are designed to address high priority education data needs; provide consistent, reliable, complete, and

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of Education, the Congress, the states, other education policymakers, practitioners, data users, and the general public.

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November 2004

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Suggested Citation

Flanagan, K., and West, J. (2004). Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal

Study, Birth Cohort (ECLS–B) (NCES 2005–036). U.S. Department of Education, Washington, DC: National Center for

Education Statistics.

For ordering information on this report, write:

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ED Pubs

P.O. Box 1398

Jessup, MD 20794–1398

Call toll free 1–877–4ED–Pubs, or order online at www.edpubs.org

Content Contact:

Jerry West

(202) 502–7335

Jerry.West@ed.gov
iii

Foreword

This E.D. TAB briefly profiles children born in the year 2001. It is the first publication based on the Early Childhood Longitudinal Study, Birth Cohort (ECLS–B).

In the base year collection of the ECLS–B, when the children were about 9 months of age, the study interviewed

parents (typically the biological mother), assessed children, and gathered information directly from the children’s

father figure. This report highlights some of these features of the ECLS–B by providing basic demographic information on the children, information on some of their specific mental and physical skills, a brief profile of their

experiences in child care, and, since the ECLS–B is one of the first national studies to collect information specifically from fathers, some descriptive information on the percentage of children with fathers in their lives.

The data analyzed in this report are now available to researchers for their own use in Electronic Codebook

(ECB) format on CD-ROM (NCES 2004–093).

We hope that the information provided in this report will be useful to a wide range of interested readers,

including both researchers and policymakers. We further hope that the results reported here will encourage

others to use the ECLS–B data, both now and in the future, as additional waves build upon this baseline.

Robert Lerner, Commissioner

National Center for Education Statistics
iv
v

Acknowledgments

Over the past 5 years, many individuals and organizations have contributed to the design and conduct of the Early

Childhood Longitudinal Study, Birth Cohort (ECLS–B). While it is not possible to name all the individuals who

have made significant contributions to this study, we would like to recognize some of those who played a critical

role during the development and implementation phases of the ECLS–B.

First, we would like to thank the 10,688 children and their parents who participated during the first wave of the

study. The parents of these children invited us into their homes and allowed us to work with their children.

A number of people contributed to the production of the E.D. TAB, and to the development of the ECLS–B more

generally. In particular, we wish to thank the ECLS–B project team (presented alphabetically, by organization):

National Center for Education Statistics Education Statistics Services Institute

Elvira Germino Hausken Frank Avenilla

Karen Manship Jodi Jacobson Chernoff

Jennifer Park Sandy Eyster

Emily Rosenthal

We would also like to recognize the people whose endless energies went into the collection of the data and to

the construction of the data file: the staff at Westat, Inc. and the Early Childhood and Household Studies staff at

the Education Statistics Services Institute.

We gratefully acknowledge Marian MacDorman of the National Center for Health Statistics for all her efforts to

make the ECLS–B a success. We wish to thank Natasha Cabrera of the University of Maryland at College Park

(and formerly with the National Institute of Child Health and Human Development) for all her work in support

of the health, special population, and father components of the study. And we wish to thank Jonaki Bose, formerly

of the National Center for Education Statistics, and Lizabeth Malone, formerly of the Education Statistics Services

Institute.

Several others have consistently given their time in support of the study, including: Victor Oliveira (Economic

Research Service, U.S. Department of Agriculture); Michael Lopez, Louisa Tarullo, and Rachel Chazen Cohen

(Administration on Children, Youth and Families, U.S. Department of Health and Human Services); Michael Kogan

(Maternal and Child Health Bureau, U.S. Department of Health and Human Services); Linda Mellgren and Martha

Moorehouse (Office of the Assistant Secretary for Planning and Evaluation, U.S. Department of Health and

Human Services); Karen Bourdon (National Institute of Mental Health, National Institutes of Health); and Howard

Hoffman (National Institute on Deafness and Other Communication Disorders, National Institutes of Health).

And, we would like to express our appreciation to the State Vital Registration and Statistics Executives who

provided the sample of 2001 birth certificates on which the study is based.

Special recognition also goes to our reviewers: Marilyn Seastrom, Kashka Kubdzela, Val Plisko, Barbara Holton,

and Bill Hussar of the National Center for Education Statistics, Dan McGrath and Lawrence Lanahan of the

Education Statistics Services Institute, Rachel Chazen Cohen of the Administration on Children, Youth and

Families, and Victor Oliveira of the Economic Research Service, for the quality of their input into this document.

A special thank you to Kendra Chandler Webb for designing the ECLS logo.
vi
vii

Contents

Foreword .................................................................................................................................................................................... iii

Acknowledgments..................................................................................................................................................................... v

List of Tables ............................................................................................................................................................................. ix

List of Figures ............................................................................................................................................................................ xi

Introduction .............................................................................................................................................................................. 1

The Current Study ............................................................................................................................................................... 2

Focus of This E.D. TAB ......................................................................................................................................................... 3

Selected Findings ....................................................................................................................................................................... 5

Demographic Characteristics of Children and Their Families................................................................................... 5

Children’s Early Mental and Physical Skills .................................................................................................................. 10

Children’s First Experiences In Child Care................................................................................................................. 14

Fathers in Children’s Lives .............................................................................................................................................. 19

Appendix A: Technical Notes and Glossary ...................................................................................................................... 23

Survey Methodology......................................................................................................................................................... 23

Response Rates ................................................................................................................................................................. 24

Data Reliability ................................................................................................................................................................... 24

Statistical Procedures ....................................................................................................................................................... 26

Glossary: Constructs and Variables Used in Analysis ................................................................................................ 27

Appendix B: Standard Error Tables ..................................................................................................................................... 31
viii
ix

List of Tables

Table Page

1. Population percentages by age of assessment: 2001 .............................................................................................. 3

2. Percentage distribution of children born in 2001, by child and family

characteristics at time of birth: 2001 ......................................................................................................................... 8

3. Percentage distribution of children born in 2001, by family characteristics

at about 9 months of age: 2001 ................................................................................................................................... 9

4. Percentage of children demonstrating specific cognitive skills, by child’s age at

assessment: 2001 .......................................................................................................................................................... 13

5. Percentage of children demonstrating specific motor skills, by child’s age

at assessment: 2001 ..................................................................................................................................................... 13

6. Percentage of children participating in child care at about 9 months of age,

by primary type of arrangement, and by child and family characteristics: 2001............................................ 17

7. Of children in child care, percentage of children by age in months when infants

first began arrangement and current weekly hours in all arrangements, by child

and family characteristics: 2001 ................................................................................................................................ 18

8. Percentage of children with or without fathers in the household around

9 months of age, by child and family characteristics: 2001................................................................................. 21

9. Of children in households where there is no resident biological father,

percentage of children with contact with their nonresident biological father, by

child and family characteristics: 2001 ...................................................................................................................... 21

Appendix B: Standard Error Tables

B-2. Standard errors for the percentage distribution of children born in 2001, by child

and family characteristics at time of birth: 2001 .................................................................................................. 32

B-3. Standard errors for the percentage distribution of children born in 2001, by family

characteristics at about 9 months of age: 2001 .................................................................................................... 33

B-4. Standard errors for the percentage of children demonstrating specific cognitive skills,

by child’s age at assessment: 2001............................................................................................................................ 34

B-5. Standard errors for the percentage of children demonstrating specific motor skills,

by child’s age at assessment: 2001............................................................................................................................ 34

B-6. Standard errors for the percentage of children participating in child care around

9 months of age, by primary type of arrangement, and by child and family characteristics: 2001 ............ 35

B-7. Standard errors for the percentage of children in care, percentage of children

by age in months when infants first began child care, and current weekly

hours in all care arrangements, by child and family characteristics: 2001 ...................................................... 36

B-8. Standard errors for the percentage of children with or without fathers in the

household around 9 months of age, by child and family characteristics: 2001.............................................. 37

B-9. Of children in households where there is no resident biological father, standard

errors for the percentage of children with contact with their nonresident

biological father, by child and family characteristics: 2001.................................................................................. 37
x
xi

List of Figures

Figure Page

1. Percentage of children born in 2001, by race/ethnicity: 2001 .............................................................................. 6

2. Percentage of children born in 2001, by mother’s age at child’s birth: 2001 .................................................... 6

3. Percentage of children born in 2001, by family type at about 9 months of age: 2001 ................................... 7

4. Percentage of children demonstrating certain mental skills at 8 to 10 months of age and at

11 to 13 months of age: 2001 ................................................................................................................................... 12

5. Percentage of children demonstrating certain physical skills at 8 to 10 months of age and at

11 to 13 months of age: 2001 ................................................................................................................................... 12

6. Percentage of children, by primary child care arrangement at about 9 months of

age: 2001 ........................................................................................................................................................................ 16

7. Percentage of children in child care, by age child first started in a regular

arrangement: 2001 ....................................................................................................................................................... 16

8. Percentage of children at about 9 months of age, by presence of a father in the

household, by race ethnicity: 2001........................................................................................................................... 20

9. Percentage of children with no biological father in their home who have never seen their

father, by race/ethnicity: 2001 ................................................................................................................................... 20
xii
1

Introduction

The National Center for Education Statistics (NCES) within the Institute of Education Sciences (IES) in collaboration with several health, education and human services agencies is conducting a new study, the Early Childhood

Longitudinal Study, Birth Cohort (ECLS–B). The ECLS–B selected a national sample of children, born in the year

2001, to follow from birth through first grade.

The National Center for Health Statistics, the National Institutes of Health (NIH), the U.S. Department of

Agriculture Economic Research Service, the Administration on Children, Youth and Families, the Maternal and

Child Health Bureau, the Office of the Assistant Secretary for Planning and Evaluation, the Centers for Disease

Control and Prevention and the Office of Minority Health, the Office of Special Education Programs, and the

Office of Indian Education are working collaboratively with NCES on the design and implementation of this

study. Sponsoring institutes from NIH are the National Institute of Child Health and Human Development, the

National Institute of Mental Health, the National Institute of Nursing Research, the National Institute on Aging,

the National Institute on Deafness and Other Communication Disorders, the National Center on Minority

Health and Health Disparities and the Office of Behavioral and Social Sciences Research.

The ECLS–B is part of a longitudinal studies program comprised of two cohorts—a birth cohort and a kindergarten cohort. Together, these cohorts provide the depth and breadth of data required to describe children’s

health, early learning, development, and education experiences.The kindergarten cohort study (ECLS-K) measures aspects of children’s development and their environments (home and school) as they enter school for the

first time and examines how these aspects relate to their academic achievement and experiences through the

fifth grade.1 The birth cohort study (ECLS–B) focuses on those characteristics of children and their families, as

well as children’s early health care and in-home and out-of-home experiences, that relate to children’s first

experiences with the demands of formal school (i.e., kindergarten and first grade). It provides important information about the way America raises, nurtures, and prepares its children for school.

This study was designed to inform an array of issues and research questions pertaining to children’s early

education, development, and care. Issues that can be addressed over the life of the study include:

■ What are children’s skills and abilities at different ages during the first six years of life? What are most

children in the United States able to do in the domains of physical, cognitive, socioemotional, and

language development at key points during these first years of life? Do the knowledge, skills, and behaviors

children demonstrate differ by race/ethnicity, socioeconomic status, family structure, and other child

and family characteristics?

■ How do children’s early health care and health status, including characteristics of children at birth

(e.g., low birth weight, multiple birth, and premature birth), relate to their preparedness for formal

school? Which groups of children seem to have more developmental difficulties and to what extent are

involvement in early intervention, early childhood education programs, and health promotion and

prevention programs associated with positive growth and development for the most vulnerable children?

1

This paper is focused on the ECLS birth cohort study. More information on the ECLS kindergarten cohort study is available from NCES at the

ECLS website (http://nces.ed.gov/ecls). For the ECLS-K, base-year data were collected from a nationally representative sample of kindergartners

attending public and private schools and early childhood programs in the fall of 1998. Follow-up waves 2, 3, and 4 were conducted in the spring

of 1999, the fall of 1999, and the spring of 2000, respectively. Wave 5 was conducted in spring 2002, and wave 6 was conducted in spring 2004,

when most of the children were in fifth grade.
2 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

■ When do children first receive regular care from someone other than their parents? What are the

characteristics of this care? How do parents make choices in determining both the timing of this care

and the nature of the child care arrangements? At what point do parents decide to place their

preschool-age child in an early childhood program? What are the characteristics of the programs that

children attend? What factors do parents consider in making this decision and in evaluating alternative

programs?

■ What role do fathers play in early child care and child-rearing and how does their involvement with

their children and the family relate to children’s school readiness? What role do resident and nonresident fathers play? Are there characteristics of fathers that are associated with individual differences in

children’s preparedness for school, independent of mother characteristics?

The Current Study

The ECLS–B is a nationally representative sample of the nearly 4 million children born in the United States in the

year 2001.2 During the first wave of the study, 10,688 parents provided information and 10,221 children were

directly assessed. The parent weight (WIR0) is the weight used to produce all estimates in this report. Only

those cases with completed parent interviews are included in this weight.3 Since the sampled children were born

between January and December 2001, baseline data were collected on a rolling basis between the fall of 2001

and the fall of 2002.

The ECLS–B was designed to collect information from children and their families for the first time when the

children were about 9 months of age (i.e., 8 to 10 months). However, information was collected from a few

children as young as 6 months and as old as 22 months. The term “9 months” is used throughout this document

to refer to the data collection that took place between fall 2001 and fall 2002, at which time most of the sampled

children were about 9 months of age (72 percent of the population was 8 to 10 months of age)

(table 1). For ease of reporting, this E.D. TAB uses the term “about 9 months of age” to refer to the entire

population of children in the study. Four additional waves of data collection are planned for when the children

are 2-year-olds, preschool-aged (e.g., age 4), and then when they are in kindergarten and first grade.

Overall, 74.1 percent of the children in the sample participated in the study. For more information on response

rates, data reliability, and test procedures, please refer to appendix A.

Comparisons made in the text were tested for statistical significance to ensure that the differences were larger

than might be expected due to sampling variation. All differences reported are significant at the p<.05 level.4

2

Sampling was based on occurence of birth as listed on the birth certificate. Sampled children subsequently identified by the state registrars as

having died or who had been adopted near or at the time of birth were excluded. However, data were collected when the children were 9

months of age, so there are some cases with adoptive parents.

3

More parents were assessed than children due to a variety of reasons, such as parents refused child assessment, child’s availability at time of

assessment (e.g., napping).

4

Other publications prepared by the National Center for Education Statistics based on the Early Childhood Longitudinal Study, Kindergarten

Class of 1998–99 (a sister study to the ECLS–B) have employed the use of effect sizes to aid in the interpretation of statistically significant

differences. These tabulations are meant to be a preliminary summative examination of the data and do not use effect size differences as a guide.
Introduction 3

Table 1. Population percentages by age of assessment

Population Population

Child and family characteristics (in thousands) percentage

Total 3,997 100

Child’s age at assessment

8, 9 or 10 months 2,756 72

8 months 613 16

9 months 1,328 35

10 months 814 21

11, 12 or 13 months 798 21

11 months 405 11

12 months 238 6

13 months 155 4

14 to 22 months 248 7

NOTE: Detail may not sum to totals because of rounding or missing data. Estimates weighted by W1R0. Children who were assessed at less

than 8 months of age (about .4 percent of the sample) are not reflected in this table; however, unless otherwise noted, these children are

included in the estimates produced in the remainder of the report.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Focus of This E.D. TAB

This E.D. TAB provides descriptive information about children born in the United States in 2001. It presents

information on certain child and family characteristics, on children’s mental and physical skills, on children’s first

experiences in child care, and on the fathers of these children. The report profiles data from a nationally representative sample of children at about 9 months of age both overall, and for various subgroups (i.e., male and

female, children from different racial/ethnic groups, and children living in different types of families).

The information in this report is presented in four sections: (1) characteristics of the children and their families;

(2) children’s early mental and physical skills; (3) children’s first experiences in child care; and (4) the fathers of

these children. The topics selected for this initial release of baseline information are only a small sampling of the

types of questions that can be addressed.

Appendixes A and B provide technical documentation for the findings presented here, as well as information

about how to obtain these data.
4
Selected FIndings 5

Selected Findings

Demographic Characteristics of Children and Their Families

Information on the demographic characteristics of the children and their families was largely provided by

the parents as part of the parent interview and also drawn from information presented on the child’s birth

certificate.

In 2001, of babies born in the United States (table 2)

■ 51 percent were boys and 49 percent were girls;

■ 54 percent were White, non-Hispanic; 14 percent were Black, non-Hispanic; 26 percent were Hispanic,

3 percent were Asian/Pacific Islanders, non-Hispanic; 1 percent were American Indian, non-Hispanic;

and 4 percent were multiracial, non-Hispanic (figure 1);

■ 3 percent of babies born were twins, less than 1 percent were part of other multiple births

(e.g., triplets, quadruplets), and 97 percent were single births;

■ 12 percent of babies were born premature, 6 percent were low birth weight (i.e., more than

3.3 pounds to 5.5 pounds), and 1 percent were very low birth weight (i.e., 3.3 pounds or less); and

■ 11 percent of babies were born to teenage mothers5 (i.e., 15 to 19 years of age) (figure 2).

When these children were about 9 months of age (table 3)

■ 23 percent were living in families whose household income was below the poverty threshold;

■ 64 percent were living with both of their married biological parents, 14 percent were living with

unmarried biological parents, and 20 percent were living with one parent (figure 3);

■ 27 percent were living with mothers who had less than a high school education, and 17 percent were

living with fathers who had less than a high school education; and

■ 24 percent were living with mothers who had a bachelor’s degree or higher, and 24 percent were living

with fathers who had a bachelor’s degree or higher.

5

Children with mothers less than 15 years of age were excluded from the study.
6 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Multiracial (4%)

White (54%)

Black (14%)

Hispanic (26%)

Asian/Pacific Islander (3%)

American Indian (1%)

Figure 1. Percentage of children born in 2001, by race/ethnicity: 2001

NOTE: Detail may not sum to totals because of rounding. White, Black, Multiracial, American Indian, and Asian/Pacific Islander all are based

on non-Hispanic children in these categories. If a child was identified as Hispanic, then he/she was reported as part of the Hispanic estimate.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

NOTE: Detail may not sum to totals because of rounding. Children with mothers less than 15 years of age were excluded from the study.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Figure 2. Percentage of children born in 2001, by mother’s age at child’s birth: 2001

30–34 years 

(24%)

35–39 years

(11%)

25–29 years

(26%)

20–24 years

(25%)

18–19 years (7%)

15–17 years (4%)

40 years or older (2%)
Selected FIndings 7

NOTE: Detail may not sum to totals because of rounding. Married, two parents and cohabiting, two parents could be one biological parent and

one nonbiological parent or two nonbiological parents (such as adoptive parents).

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Figure 3. Percentage of children born in 2001, by family type at about 9 months of age: 2001

Married, two biological 

parents (64%)

Married, two parents (1%)

Cohabiting, two biological parents (14%)

Cohabiting, two parents (1%)

Single parent (20%)

Other (guardian) (1%)
8 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Table 2. Percentage distribution of children born in 2001, by child and family

characteristics at time of birth: 2001

Population Population

Child and family characteristics (in thousands) percentage

Total 3,997 100

Child’s sex

Male 2,041 51

Female 1,956 49

Child’s race/ethnicity

White, non-Hispanic 2,133 54

Black, non-Hispanic 547 14

Hispanic 1,018 26

Asian, non-Hispanic 111 3

Native Hawaiian or Other Pacific Islander, non-Hispanic 7 #

American Indian, non-Hispanic 20 1

Multiracial, non-Hispanic 151 4

Birth status

Single 3,864 97

Twin 119 3

Higher order (e.g., triplet) 7 #

Prematurity (less than 37 weeks gestation)

No 3,529 88

Yes 462 12

Birth weight

Normal birth weight (more than 5.5 pounds) 3,696 93

Moderately low birth weight (more than 3.3 to 5.5 pounds) 248 6

Very low birth weight (3.3 pounds or less) 51 1

Child’s mother’s age at child’s birth1

15-17 years 144 4

18-19 years 296 7

20-24 years 1,011 25

25-29 years 1,054 26

30-34 years 938 24

35-39 years 451 11

40 years or older 97 2

# Rounds to zero.

1

Children with mothers less than 15 years of age were excluded from the study.

NOTE: Detail may not sum to totals because of rounding or missing data. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).
Selected FIndings 9

Table 3. Percentage distribution of children born in 2001, by family characteristics at about

9 months of age: 2001

Population Population

Child and family characteristics percentage (in thousands)

Total 3,997 100

Poverty status

Below poverty threshold 914 23

At or above poverty threshold 3,083 77

Family type

Married, two biological parents 2,574 64

Married, two parents 19 1

Cohabiting, two biological parents 541 14

Cohabiting, two parents 29 1

Single parent live alone 812 20

Other (guardian) 21 1

Child’s mother’s education1

Less than high school 1,091 27

High school diploma/GED 865 22

Some college/votech certificate 1,047 26

Bachelor’s degree or higher 974 24

Child’s father’s education2

Less than high school 691 17

High school diploma/GED 732 18

Some college/votech certificate 834 21

Bachelor’s degree or higher 941 24

1

Mother’s education reflects the population of children living with their mother; therefore, estimates may not sum to totals for mother’s

education due to the omitted category “no mother in household.”

2

Father’s education reflects the population of children living with their father. Therefore estimates may not sum to totals for father’s

education due to the omitted category “no father in household.”

NOTE: Detail may not sum to totals because of rounding or missing data. Married, two parents and cohabiting, two parents could be one

biological parent and one nonbiological parent or two nonbiological parents (such as adoptive parents). Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).
10 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Children’s Early Mental and Physical Skills

The ECLS–B assessment of young children’s mental and motor development relies on a direct measure of

children—the Bayley Short Form–Research Edition (BSF–R), which was developed for use in the ECLS–B. The

BSF–R is a shortened version of the Bayley Scales of Infant Development–Second Edition (BSID–II) (Bayley

1993)6

, a standardized assessment of mental and motor developmental status for children from birth to

42 months of age.

This E.D. TAB presents information on young children’s specific mental and physical skills (i.e., proficiencies).

Proficiency scores provide a means of distinguishing status in specific skills within a content area. Clusters of two

to five test questions having similar content and difficulty were included at several points along the score scale of

the BSF–R mental and physical assessments. Clusters of items provide a more reliable test of proficiency than do

single items.7

Below are the five proficiencies for early mental skills.

■ Exploring Objects. The child is reaching for and holding objects, he/she may have no specific purpose

or goal except to play or discover.

■ Exploring Objects With a Purpose. The child is manipulating objects with a purpose (e.g., to see

what makes the ringing sound in a bell).

■ Babbling. The child is making simple sounds and gestures (e.g., babbling or jabbering).

■ Early Problem Solving. The child is using reasoning to interact with objects (e.g., if a toy is out of

reach, using another object, like another toy, to bring the desired toy within reach).

■ Communicating With Words. The child understands and uses words, both receptively (pointing to

named objects) and expressively (saying words).

Below are the five proficiencies for early physical skills.

■ Eye-hand Coordination. The child demonstrates eye-hand coordination as he/she reaches for objects.

■ Sitting. The child can sit alone, without leaning against something or other assistance.

■ Prewalking. The child is taking steps and supporting his/her weight while standing, with assistance

(moving along furniture or holding onto someone’s hand).

■ Independent Walking. The child is walking alone, without assistance (without holding onto something or someone).

■ Balance. The child can balance in various positions (e.g., squatting, standing on one foot).

The ECLS–B was designed to collect information from children and their families for the first time when the

children were about 9 months of age (i.e., 8 to 10 months). However, information was collected from a few

children as young as 6 months and as old as 22 months. Young children’s mental and physical skills develop rapidly.

Therefore, this E.D. TAB presents information on young children’s skills by their age at assessment, in several

6

Bayley, N. (1993). Bayley Scales of Infant Development, Second Edition Manual. San Antonio, TX: The Psychological Corporation.

7

For more information on the content, administration, and properties of the direct child assessment, please refer to appendix A of the E.D. TAB.
Selected FIndings 11

ways. First, this E.D. TAB presents information on the children in the sample 8 to 10 months of age at the

time of assessment. Next, the E.D. TAB presents information on the children in the sample who were 11 to 13

months of age at the time of assessment. Tables 4 and 5 present a breakdown by age (i.e., age at assessment,

month by month).8

When children were 8 to 10 months old , in terms of their mental skills (table 4, figure 4)

■ 99 percent were exploring objects in play;

■ 88 percent were exploring objects with a purpose;

■ 47 percent were babbling;

■ 3 percent were demonstrating early problem solving; and

■ less than 1 percent were using words.

When children were 8 to 10 months old, in terms of their physical skills (table 5, figure 5)

■ 91 percent demonstrated eye-hand coordination;

■ 93 percent were sitting;

■ 73 percent were showing prewalking skills;

■ 19 percent were walking; and

■ 1 percent could balance.

When children were 11 to 13 months old, in terms of their mental skills (table 4, figure 4)

■ 100 percent were exploring objects in play;

■ 97 percent were exploring objects with a purpose;

■ 72 percent were babbling;

■ 17 percent were demonstrating early problem solving; and

■ 5 percent were using words.

When children were 11 to 13 months old, in terms of their physical skills (table 5, figure 5)

■ 96 percent demonstrated good eye-hand coordination;

■ 98 percent were sitting;

■ 91 percent were showing prewalking skills;

■ 55 percent were walking; and

■ 10 percent could balance.

8

This E.D. TAB does not present information on children’s mental and physical skills by characteristics such as children’s sex, race/ethnicity, and

poverty status. Preliminary analyses revealed that, for the most part at this age the mental and physical skills discussed in this report do not

significantly differ by children’s sex, race/ethnicity, and poverty status. A future NCES report will examine group differences in children’s mental

and physical skills in more detail, presenting information from the 9-month collection and the 2-year collection of the ECLS-B.
12 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

# Less than .5 percent.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percent

99 100

88

97

47

72

3

17

#

5

8 to 10 months

11 to 13 months

0

20

40

60

80

100

Explores objects 

in play

Explores with 

purpose Babbles Early problem solving

Uses words

Figure 4. Percentage of children demonstrating certain mental skills at 8 to 10 months of age

and at 11 to 13 months of age: 2001

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Figure 5. Percentage of children demonstrating certain physical skills at 8 to 10 months of age

and at 11 to 13 months of age: 2001

Percent

8 to 10 months

11 to 13 months

Eye hand 

coordination

Sitting Prewalking Walking Balance

0

20

40

60

80

100

91

96 93

98

73

91

19

55

1

10
Selected FIndings 13

Table 4. Percentage of children demonstrating specific cognitive skills, by child’s age at

assessment: 2001

Explores Explores Early

Population objects with problem Uses

Child characteristics percentage in play purpose Babbles solving words

Child’s age at assessment

 8, 9 or 10 months 72 99 88 47 3 #

 8 months 16 99 80 38 1 #

 9 months 35 99 88 45 3 #

 10 months 21 99 94 56 6 1

11, 12 or 13 months 21 100 97 72 17 5

 11 months 11 100 96 65 11 3

 12 months 6 100 99 77 20 6

 13 months 4 100 99 84 28 10

14 to 22 months 7 100 99 89 46 27

# Rounds to zero.

NOTE: Children who were assessed at less than 8 months of age (about .4 percent of the sample) are not reflected in this table; however,

unless otherwise noted, are included in the estimates produced in the remainder of the report. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percentage of children demonstrating specific cognitive abilities

Table 5. Percentage of children demonstrating specific motor skills, by child’s age at

assessment: 2001

Population Eye-hand Independent

Child characteristics percentage coordination Sitting Prewalking walking Balance

Child’s age at assessment

 8, 9 or 10 months 72 91 93 73 19 1

 8 months 16 88 90 63 10 #

 9 months 35 91 93 73 17 1

 10 months 21 93 96 81 27 2

11, 12 or 13 months 21 96 98 91 55 10

 11 months 11 95 97 88 43 5

 12 months 6 97 99 94 62 13

 13 months 4 98 99 96 76 20

14 to 22 months 7 99 100 98 89 43

# Rounds to zero.

NOTE: Children who were assessed at less than 8 months of age (about .4 percent of the sample) are not reflected in this table; however,

unless otherwise noted are included in the estimates produced in the remainder of the report. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percentage of children demonstrating specific motor abilities
14 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Children’s First Experiences in Child Care

As part of the parent interview, information was collected on children’s first experiences in child care. Parents

provided information on whether their child was in care, the type of care, the number of hours in care, and the

age at which the child first entered care. The ECLS–B seeks to provide information on the care that young

children receive on a regular basis from persons other than their parents.9

■ When children were about 9 months of age, approximately one-half (50 percent) were in some kind of

regular child care arrangement, such as a center-based care arrangement or care provided by a nonrelative

or relative in a private home (figure 6, table 6).

■ Black children (63 percent) were more likely to be in some kind of child care arrangement, compared

to White (49 percent), Hispanic (46 percent), and Asian children (47 percent). Children whose mothers

work (full time or part time) are more likely to be in child care than children whose mothers do not

work or who are looking for work. Children in families who were not poor (at or above the poverty

threshold) (52 percent) were more likely to be in child care than children from poor families

(43 percent) (table 6).

■ Among children about 9 months of age (figure 6, table 6)

- 26 percent were in relative care as their primary arrangement,10 where they

received care from someone related to them other than the parent, such as a

grandparent, aunt, uncle, sibling, or some other relative. Relative care could be in

the child’s home or in the home of the caregiver.

- 15 percent were in nonrelative care as their primary arrangement, care provided

by someone who is not related to them, such as a nanny, home-based care provider,

regular sitter, or neighbor. This does not include day care centers or preschools.

The care could be in the child’s home or in the home of the caregiver.

- 9 percent were in center-based care as their primary arrangement, such as early

learning centers, nursery schools, and preschools (including Early Head Start).

- 1 percent had a primary arrangement that was actually multiple arrangements,

where they spent equal numbers of hours across different care arrangement types

(such as 20 hours a week with a relative and 20 hours a week in a center-based

program).

9

Parents include biological and adoptive parents as well as stepparents and guardians.

10Primary care arrangement is where the child spends the most hours. If the child spent equal time across two or more arrangements, primary

care was classified as multiple arrangements.
Selected FIndings 15

■ The type of child care children receive varied by their race/ethnicity. Black children were more likely

than White, Hispanic, or Asian children to be in center-based care. White children were less likely than

Black, Hispanic, or Asian children to be cared for by a relative (table 6).

■ Of children in child care, 39 percent began when they were younger than 3 months, 47 percent were

three to six months old, and 14 percent started care when they were older than 6 months (figure 7,

table 7). In terms of hours per week in child care, 19 percent of children about 9 months of age were

in an arrangement 10 hours or fewer, 27 percent were in an arrangement 11 to 30 hours, 31 percent

were in an arrangement 31 to 40 hours, and 24 percent were in an arrangement more than 40 hours

(table 7).

■ The age at which children entered child care and the number of hours they spent in the arrangement

varied by their race/ethnicity. Asian children were more likely than White, Black, or Hispanic children

to enter a child care arrangement when they were younger than 3 months of age. Asian children were

more likely than White, Black, or Hispanic children to spend more than 40 hours a week in care, and

Black children were more likely than White or Hispanic children to spend more than 40 hours a week

in care.

■ Children in relative care were more likely to be in care for 10 hours or fewer a week than children in

nonrelative care or a center-based program. Children in multiple care arrangements were more likely

to be in care more than 40 hours a week than children in a single care arrangement.
16 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

NOTE: Detail may not sum to totals because of rounding.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Less than 3 months (39%)

 3–6 months (47%)

Older than 6 months (14%)

Figure 7. Percentage of children in child care, by age child first started in a regular arrangement: 2001

NOTE: Detail may not sum to totals because of rounding.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Multiple arrangements (1%)

No child care (50%)

Relative care (26%)

Nonrelative care (15%)

Center-based care (9%)

Figure 6. Percentage of children, by primary child care arrangement at about 9 months of age: 2001
Selected FIndings 17

Table 6. Percentage of children participating in child care at about 9 months of age, by

primary type of arrangement, and by child and family charactersitics: 2001

Relative Nonrelative Center-based Multiple No regular

Child and family characteristics care care care arrangements arrangement

Total 26 15 9 1 50

Child’s sex

Male 26 15 9 1 50

Female 26 16 8 1 50

Child’s race/ethnicity

White, non-Hispanic 21 17 9 1 51

Black, non-Hispanic 33 15 14 1 37

Hispanic 30 11 5 # 54

Asian, non-Hispanic 33 10 4 # 53

Other, non-Hispanic1 28 14 10 1 46

Mother’s employment status

Full time (35 hours or more) 39 29 17 1 15

Part time 38 21 8 2 33

Looking for work 22 6 7 # 65

Not in work force 9 4 3 # 84

No mother in household 37 2 17 # 45

Poverty status

Below poverty threshold 28 8 7 1 57

 At or above poverty threshold 25 17 9 1 48

# Rounds to zero.

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Detail may not sum to totals because of rounding. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Care arrangement
18 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Table 7. Of children in child care, percentage of children by age in months when infants

first began arrangement and current weekly hours in all arrangements, by child

and family characteristics: 2001

Younger More 10 hours

than 3 3 to 6 than 6 or 11 to30 31 to 40 More than

Child and family characteristics months months months fewer hours hours 40 hours

Total 39 47 14 19 27 31 24

Child’s sex

Male 39 47 14 19 28 31 22

Female 39 46 14 18 27 31 25

Child’s race/ethnicity

White, non-Hispanic 39 47 14 21 29 30 21

Black, non-Hispanic 40 45 15 12 23 36 29

Hispanic 39 47 14 20 26 31 23

Asian, non-Hispanic 50 37 13 17 20 27 36

Other, non-Hispanic1 38 49 13 12 31 33 24

Poverty status

Below poverty threshold 41 41 18 18 31 31 20

At or above poverty threshold 39 48 13 18 26 31 24

Mother’s employment status

Full time (35 hours or more) 44 46 11 10 15 42 33

Part time 30 52 18 26 49 15 9

Looking for work 42 41 17 20 33 28 19

Not in work force 37 44 19 39 29 17 15

No mother in household 49 16 35 11 20 37 32

Primary care arrangement

Relative care 42 44 14 22 31 27 21

Nonrelative care 37 50 14 17 27 34 23

Center care 38 46 16 12 17 41 31

Multiple arrangements 40 43 17 13 22 5 58

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Detail may not sum to totals because of rounding. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Age first began care Total hours in child care arrangement(s)
Selected FIndings 19

11In the ECLS–B, this was by design. When the home visit was conducted, the interviewer specifically asked for the biological mother to be the

respondent. Data not shown in table.

Fathers in Children’s Lives

As part of the parent interview, information was collected on whether or not there was a father in the household (e.g., biological, nonbiological, no resident father) and if there was no resident biological father in the

household, then information was collected on the amount of contact the biological father had with the child.

■ When children were about 9 months of age, 1 in 5 (20 percent) lived in households with no father

(table 8).

■ Black children (58 percent) were more likely than White children (10 percent), Hispanic children

(20 percent), or Asian children (6 percent) to live in a household with no father present (figure 8, table

8). Forty-five percent of children living below the poverty threshold lived in households with no father

present, while 12 percent of children living at or above the poverty threshold lived in households

without a father.

■ In the ECLS–B, in about 99 percent of the interviews, the biological mother was the respondent.11

According to the child’s mother, when there was no resident biological father in the household (table 9)

- 40 percent of young children had contact with their father the same day as the

home visit (when the parent interview was conducted);

- 38 percent of children had contact with their father within 2 to 7 days

of the home visit;

- 7 percent of children had contact with their father within the last 8 to 14 days of

the home visit;

- 2 percent of children had not seen their father in more than 2 weeks; and

- 13 percent of children had never seen their father.

■ Of children with no resident father, 6 percent of Black children had nonresident fathers who had never

had contact with them, compared to 18 percent of White children, 21 percent of Hispanic children, and

25 percent of Asian children (figure 9, table 9).
20 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

NOTE: Details may not sum to totals because of omitted category nonbiological father in household.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percent

White Black Hispanic Asian Other

No resident father

0

20

40

60

80

100

88

41

78

93

74

10

58

20

6

25

Biological resident father

Figure 8. Percentage of children at about 9 months of age, by presence of a father in the

household, by race/ethnicity: 2001

Figure 9. Percentage of children with no biological father in their home who have never

seen their father, by race/ethnicity: 2001

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percent

White Black Hispanic Asian Other

0

20

40

60

80

100

18

6

21 25

12

Percentage of children with no biological father 

in their home who have never seen their father
Selected FIndings 21

Table 8. Percentage of children with or without fathers in the household around 9 months

of age, by child and family charactersitics: 2001

Non- No father

Child and family characteristics All children Biological biological in household

Total 100 79 1 20

Child’s sex

Male 51 79 1 19

Female 49 78 1 20

Child’s race/ethnicity

White, non-Hispanic 54 88 2 10

Black, non-Hispanic 14 41 1 58

Hispanic 25 78 1 20

Asian, non-Hispanic 3 93 # 6

Other, non-Hispanic1 4 74 1 25

Poverty status

Below poverty threshold 23 53 1 45

At or above poverty threshold 77 86 1 12

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Detail may not sum to totals because of rounding. In the absence of a biological parent, the father designation (i.e., nonbiological) was

assigned to the adoptive, step, foster/guardian, partner (including household members defined as spouses/partners of the parent respondent

but were not identified by the respondent as mothers/female guardians or fathers/male guardians), or “unknown-type” parent. Estimates

weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Father in household

Visited child Visited child Visited child More than 2

the same day in the in the weeks since Never

as parent past 2 past 8 last visited seen

Child and family characteristics interview to 7 days to 14 days child child

Total 40 38 7 2 13

Child’s sex

Male 39 37 7 3 13

Female 40 38 6 2 14

Child’s race/ethnicity

 White, non-Hispanic 33 41 7 1 18

Black, non-Hispanic 49 37 6 3 6

Hispanic 34 35 7 3 21

Asian, non-Hispanic 23 37 14 2 25

Other, non-Hispanic1 40 42 5 2 12

Poverty status

Below poverty threshold 42 37 6 3 12

At or above poverty threshold 37 39 7 2 15

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Detail may not sum to totals because of rounding. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Nonresident biological father’s contact with child

Table 9. Of children in households where there is no resident biological father, percentage of

children with contact with their nonresident biological father, by child and family

charactersitics: 2001
22
Appendix A: Technical Notes and Glossary 23

Appendix A

Technical Notes and Glossary

Survey Methodology

The Early Childhood Longitudinal Study, Birth Cohort (ECLS–B) is sponsored by the U.S. Department of Education,

Institute of Education Sciences, National Center for Education Statistics (NCES). The ECLS–B is designed to

provide detailed information on children’s development, health, and in- and out-of-home experiences in the

years leading up to school. The children participating in the ECLS–B are being followed longitudinally for 6 years

(through first grade). Estimates in this report are based on data collected from and about children during the

first wave of data collection when they were approximately 9 months old. Westat, Incorporated conducted the

first wave of the study.

A nationally representative sample of 10,688 children born in the United States in 2001 and/or their parents

participated in the ECLS–B. The sample includes children from different racial/ethnic and socioeconomic backgrounds, and includes oversamples of Chinese and other Asian and Pacific Islander children, American Indian

children, twins, and children with moderately low and very low birth weight.

The sample of infants was selected using a clustered, list frame sampling design. The list frame was registered

births in the National Center for Health Statistics’ (NCHS) vital statistics system (from lists provided by state

registrars). Births were sampled from 96 core primary sampling units (PSU) representing all infants born in the

United States in the year 2001. The PSUs were counties and county groups. To support the American Indian

oversample, 18 additional PSUs were selected from a supplemental frame consisting of areas where the population has a higher proportion of American Indian births (for more information see section 4.1.3 in the ECLS–B

9-month Data File User’s Manual12). Sampling was based on occurrence of the birth as listed on the birth certificate. Sampled children subsequently identified by the state registrars as having died or who had been adopted

after the issuance of the birth certificate were excluded from the sample.13 Also, infants whose birth mothers

were younger than 15 years at the time of the child’s birth were excluded.

The 9-month data were obtained from October 2001 through December 2002, during a visit in the child’s home.

This E.D. TAB presents information from the child assessments, parent interviews, and father questionnaires.

Each of these are described below.

■ Child Assessments. Children participated in a variety of activities, with the parent’s permission, to

assess their early cognitive (e.g., mental status), physical, and socioemotional development. This report

uses information from the mental and motor assessment. Children’s mental and physical skills were

measured through an untimed one-on-one assessment of the child in his/her home. A trained staff

member assessed each child. Information was gathered using hard copy materials. Information about

the child was recorded in a Child Activities Booklet that also contained administration and scoring

instructions. The assessment—the Bayley Short Form–Research Edition (BSF–R)—measured children’s

mental and physical skills. For families whose primary language was not English, the assessment was still

administered. A Spanish version of the Child Activities Booklet was developed. If the family spoke a

language other than English or Spanish, interviewers used an interpreter.

12National Center for Education Statistics (2004). Early Childhood Longitudinal Study, Birth Cohort: 9-month Restricted-Use Data Files User’s Manual

(NCES 2004–093). Washington, DC: National Center for Education Statistics.

13Children adopted near or at the time of birth were excluded. However, data was collected when the children were 9 months of age, so there

are some cases with adoptive parents.
24 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

■ Parent Interviews. Parents/guardians were asked to provide key information about their children

and themselves on such topics as family demographics (e.g., age, relation to child, race/ethnicity), family

structure (household members and composition), parent attitudes, home educational activities, child

care experience, child development and health, and parental education and employment status. In 99

percent of the cases, the biological mother was the parent respondent completing the interview. The

parent interview included two instruments: the parent interview instrument and the parent self-administered questionnaire (PSAQ). The first was conducted in person by trained field interviewers using

computer-assisted personal interviewing (CAPI) as part of the home visit. The PSAQ was a paper-andpencil instrument, presented during the parent CAPI instrument for the respondent to complete and

return in a provided envelope, and contained 23 questions on topics some people might prefer to

answer privately. The parent interviews were conducted primarily in English, but provisions were made

to interview parents who spoke other languages. Bilingual interviewers were trained to conduct the

parent interview in either English or Spanish. A Spanish CAPI instrument was used when needed as

the parent CAPI instrument was programmed in both English and Spanish. An interpreter, either a

community or household member, was used for families who spoke languages other than English or

Spanish. Fewer than 0.1 percent of the cases were not completed due to language difficulties.

■ Father Questionnaires. Although the information in this E.D. TAB comes largely from the child

assessment and the parent interview, the ECLS–B also collected data from fathers directly through two

separate father questionnaires: the resident father questionnaire and the nonresident father questionnaire. Both father questionnaires were self-administered with telephone follow up. The father

questionnaires were available in English and Spanish.

For more information on any of the components of the ECLS–B, please refer to the ECLS–B 9-month Data File

User’s Manual.14

Response Rates

The ECLS–B is a nationally representative sample of the nearly 4 million children born in the United States in the

year 2001. The response rate for the 9-month data collection was 74.1 percent, based on weighted data (i.e.,

using the base weights). The response rate is the number of completed parent interviews divided by the total

eligible sample. To be considered complete, the first three sections of the parent interview had to be completed.

Data Reliability

With the exception of key variables the ECLS–B does not impute. The item response rate for all variables used

in this report exceeded 90 percent.

Estimates produced using data from the ECLS–B are subject to two types of error, sampling and nonsampling

errors. Nonsampling errors are errors made in the collection and processing of data. Sampling errors occur

because the data are collected from a sample rather than a census of the population.

Nonsampling Errors. Nonsampling error is the term used to describe variations in the estimates that may be

caused by population coverage limitations, as well as data collection, processing, and reporting procedures.

14National Center for Education Statistics (2004). Early Childhood Longitudinal Study, Birth Cohort: 9-month Restricted-Use Data Files User’s Manual

(NCES 2004–093). Washington, DC: National Center for Education Statistics.
Appendix A Technical Notes and Glossary 25

The sources of nonsampling errors are typically problems like unit and item nonresponse, the differences in

respondents’ interpretations of the meaning of the questions, response differences related to the particular time

the survey was conducted, and mistakes in data preparation.

In general, it is difficult to identify and estimate either the amount of nonsampling error or the bias caused by this

error. In the ECLS–B, efforts were made to prevent such errors from occurring and to compensate for them

where possible. The design phase entailed a pilot test of the Bayley Short Form–Research Edition (BSF-R) and a

field test that evaluated the implementation of the study. In the main study administration of the BSF-R, there

was rigorous training, certification, and monitoring of the assessors administering the instrument.

Another potential source of nonsampling error is respondent bias that occurs when respondents systematically

misreport (intentionally or unintentionally) information in a study. One potential source of respondent bias in

this survey is social desirability bias. If there are no systematic differences among specific groups under study in

their tendency to give socially desirable responses, then comparisons of the different groups will accurately

reflect differences among the groups. An associated error occurs when respondents give unduly positive assessments about those close to them. For example, parents may give higher assessments of their children’s motor

accomplishments (like feeding themselves) than might be obtained from direct assessment.

Readers should be aware that respondent bias may be present in this survey as in any survey. It is not possible to

state precisely how such bias may affect the results. NCES has tried to minimize some of these biases by

conducting one-on-one, untimed assessments, and by asking some of the same questions about the sampled

child of both the mother and father (e.g., activities the father engages in with the child).

A nonresponse bias analysis was conducted (Early Childhood Longitudinal Study, Birth Cohort [ECLS-B],

Sampling Report for the Nine-Month Data Collection, U.S. Department of Education, National Center for

Education Statistics, forthcoming.) The evaluation consisted of the following elements:

■ evaluation of response rates;

■ comparison of frame data between respondents and nonrespondents;

■ comparison of survey data between respondents and “proxy” nonrespondents;

■ sensitivity analysis of potential for nonresponse;

■ comparison of ECLS-B data with other surveys; and

■ analysis of factors that influence likelihood of survey response; and

■ evaluation of the impact of substitution on nonresponse bias.

The analysis benefited from the unusually rich information available on the frame. The birth record contains

a number of important variables on the mother and the child that support many comparisons between

respondents and nonrespondents. Findings from these analyses suggest that there is not a bias due to nonresponse.

Sampling Errors and Weighting. The sample of children born in the United States during 2001 was just one

of many possible samples of 2001 births that could have been selected. Therefore, estimates produced from the

ECLS–B sample may differ from estimates that would have been produced from other samples. This type of

variability is called sampling error because it arises from using a sample of children, rather than all children born

in 2001.
26 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

The standard error is a measure of variability due to sampling when estimating a statistic. Standard errors for

estimates presented in this report were computed using a jackknife replication method. Standard errors can be

used as a measure for the precision expected from a particular sample. The probability that a complete census

count would differ from the sample estimate by less than 1 standard error is 68 percent. The chance that the

difference would be less than 1.65 standard errors is about 90 percent, and that the difference would be less

than 1.96 standard errors, about 95 percent.

In order to produce national estimates from the ECLS–B data collected during the 9-month data collection, the

sample data were weighted. Weighting the data adjusts for unequal selection probabilities at the child level and

the weights are adjusted for unit nonresponse. The parent weight (W1R0), which is the weight used to produce

all estimates found in this report, is the weight that accounts for the probability of selection in the sample as well

as nonresponse to the parent interview. Only those cases with completed parent interviews in the 9-month data

collection are included in this weight. A parent interview is considered complete if the first three sections were

finished (IN, FS, CD). The parent weight sums to the population of all parents of children born in the United

States in 2001. The approach used to develop weights for the ECLS–B is described in Chapter 4 of the ECLS–B

9-month Data File User’s Manual.

15

In addition to properly weighting the responses, special procedures for estimating the statistical significance of

the estimates were employed because the data were collected using a complex sample design. Complex sample

designs, like that used in the ECLS–B, result in data that violate the assumptions that are normally required to

assess the statistical significance of the results. Frequently, the standard errors of the estimates are larger than

would be expected if the sample was a simple random sample and the observations were independent and

identically distributed random variables.

Replication methods of variance estimation were used to reflect the actual sample design used in the ECLS–B.

A form of the jackknife replication method (JK2) using 84 replicate weights was used to compute approximately

unbiased estimates of the standard errors of the estimates in the report, using WesVar version 4.0. Jackknife

methods were used to estimate the precision of the estimates of the reported national percentages and means.

The standard errors of the estimates are presented in appendix B of this E.D. TAB.

Statistical Procedures

Comparisons made in the text were tested for statistical significance to ensure that the differences were larger

than might be expected due to sampling variation. When comparing estimates between categorical groups

(e.g., sex, race/ethnicity), t statistics were calculated. The formula used to compute the t statistic was:

t = Est1 – Est2 / SQRT[(se1)2

 + (se2)2]

Where Est1 and Est2 are the estimates being compared and se1 and se2 are their corresponding standard

errors. All differences reported are significant at the p<.05 level.

15National Center for Education Statistics (2004). Early Childhood Longitudinal Study, Birth Cohort: 9-month Restricted-Use Data Files User’s Manual

(NCES 2004–093). Washington, DC: National Center for Education Statistics.
Appendix A Technical Notes and Glossary 27

Glossary: Constructs and Variables Used in Analysis

Child and Family Characteristics

Several of the variables used in this report were derived by combining information from one or more questions

in the ECLS–B parent CAPI instrument or from other study sources. The name of the source variable as presented on the ECLS–B Restricted-Use Data File is shown after the description in all capital letters within

brackets. More information on the derivation of key variables is described in chapter 7 of the ECLS–B 9-month

Data File User’s Manual.

16

■ Children’s sex [X1CHSEX] This composite is mainly taken from the birth certificate information

used for sampling and the information was confirmed in the parent interview. If the parent interview

indicated a sex different from the birth certificate, then the parent interview information took priority.

■ Children’s race/ethnicity [X1CHRACE] Parent respondents were allowed to indicate that the

child belonged to one or more of 14 race categories. These categories include (1) White, (2) Black or

African American, (3) American Indian or Alaska Native, (4) Asian Indian, (5) Chinese, (6) Filipino, (7)

Japanese, (8) Korean, (9) Vietnamese, (10) Other Asian, (11) Native Hawaiian, (12) Guamanian or

Chamorro, (13) Samoan, and (14) Other Pacific Islander. From these responses, a series of six dichotomous race variables were created that indicated separately whether the child belonged to each of five

main specified race groups, including White, Black, Asian (including Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, and Other Asian), American Indian, and Native Hawaiian or other Pacific

Islander (including Native Hawaiian, Guamanian or Chamorro, Samoan, and Other Pacific Islander). In

addition, one more dichotomous variable was created for parent respondents who had simply indicated that the child was multiracial without specifying a race (e.g., biracial). Data were collected on

ethnicity as well. Specifically, respondents were asked whether the child was of Hispanic or Latino

origin. Using the six race dichotomous variables and the Hispanic ethnicity variable, the race/ethnicity

composite variable (X1CHRACE) was created. The categories were White, non-Hispanic; Black or

African American, non-Hispanic; Hispanic, race specified; Hispanic, no race specified; Asian, non-Hispanic; Native Hawaiian or other Pacific Islander, non-Hispanic; American Indian or Alaska Native, nonHispanic; and more than one race specified, non-Hispanic. A child was classified as Hispanic if a parent

respondent indicated the child’s ethnicity was Hispanic regardless of whether a race was identified and

what that race was.

■ Children’s birth status [X1MBRTST] This composite is derived from information on the birth

certificate that states whether the child was part of a single birth, twin birth, or other multiple births

(e.g., triplets, quadruplets).

■ Children’s prematurity [BCGESTWK] This is variable from the birth certificate that presents

information on gestational age in weeks—36 weeks or less is considered premature.

■ Children’s birth weight [X1BTHWGT] Child’s birth weight is derived from information on the

birth certificate and then categorized into “normal” (greater than 5.5 pounds), “low” (more than 3.3

pounds to 5.5 pounds), and “very low” (less than 3.3 pounds).

16National Center for Education Statistics (2004). Early Childhood Longitudinal Study, Birth Cohort: 9-month Restricted-Use Data Files User’s Manual

(NCES 2004–093). Washington, DC: National Center for Education Statistics.
28 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

■ Maternal age at child’s birth [BCMOMAGE] This is a single variable that is drawn from the birth

certificate that presents the child’s mother’s age in years at the time of the child’s birth.

■ Poverty status [X1POVRTY] Total household income was compared to Census poverty thresholds for 2001, which vary by household size. For example, if the household income was lower than

$11,920, then the household was considered to be below 100 percent of the poverty threshold. Or for

a household of four, a household income of $18,104 was considered to be below 100 percent of the

poverty threshold.

■ Family type [derived from: X1MARSTA; P1PARTNR; P1NFTHHH] In order to construct this

family type variable, information from X1MARSTA (marital status of parent—married, separated, divorced, widowed), P1PARTNR (spouse or partner living in the household), and P1NFTHHH (confirmation of biological father not living in household) was used. Married, two biological parents includes biological mothers and biological fathers who are married. Married, two parents includes biological mother and

other father, biological father and other mother, two adoptive parents, or two same sex parents. Cohabiting, two biological parents includes unmarried biological mother and father. Cohabiting, two parents

includes unmarried biological mother and other father, biological father and other mother, or two same

sex parents. Single parent live alone includes a single biological mother, a single biological father or a

single adoptive parent. Other (guardian) includes related guardians or unrelated guardians, and/or

foster parents.

■ Mother’s education [X1MOMED] This composite presents the highest level of education the

mother completed. This variable includes only birth, adoptive, step-, or foster mothers residing in the

household. For example, if the child did not have birth, adoptive, step-, or foster parents but was living

with another relative (such as an aunt) who served as the parent respondent, the education of the

relative and his or her spouse was not used in the creation of the composites. At 9 months of age, less

than one percent of the children did not have at least one parent in the household.

■ Father’s education [X1FTHED] This composite presents the highest level of education the father

completed. Information on father education was collected directly from fathers. If the father was the

respondent to the parent interview, the information from the parent interview was used. If the father

was not the respondent to the parent interview, information from the father questionnaires was used.

If the father was not the respondent to the parent interview and father education was missing on the

father questionnaires, information on father education provided by the respondent to the parent interview was used.This variable includes only birth, adoptive, step-, or foster fathers residing in the household. For example, if the child did not have birth, adoptive, step-, or foster parents but was living with

another relative (such as an aunt) who served as the parent respondent, the education of the relative

and his or her spouse was not used in the creation of the composites. At 9 months of age, less than one

percent of the children did not have at least one parent in the household.

■ Children’s age at assessment [X1ASAGE] The composite variable X1ASAGE defines child’s age

at assessment in terms of the child’s chronological age in decimal months. If the child’s date of birth on

the birth record was determined to be correct by the parent respondent, then the child’s age was

calculated by determining the number of days between the date when the child completed the

ECLS–B direct child assessments and the child’s date of birth indicated on the birth record. If the child’s

date of birth on the birth record was determined to be incorrect by the parent respondent, then the
Appendix A Technical Notes and Glossary 29

child’s age was calculated by determining the number of days between the date when the child completed the direct child assessment and the child’s date of birth reported in the parent CAPI instrument.

The total number of days was then divided by 30 to calculate the age in months.

■ Primary care arrangement [X1PRIMNW] This composite presents information on the type of

care in which the child spent the most hours. To create the composite, the hours for relative care,

nonrelative care, and center-based care were compared to select the primary care arrangement with

the most number of hours. If the number of hours of care was equal for two or more types of care,

X1PRIMNW was coded as “multiple care arrangements.” If the indicator variables for regular receipt of

relative, nonrelative, and center-based care all equal to “no care,” then X1PRIMNW was coded as “no

child care.” Note, the term “regular” is not specifically defined to the respondent; therefore, the respondent interprets “regular” as whatever it means to them.

■ Age first began care [X1AGCARE] This composite indicates the earliest age in months the child

first began any type of child care on a regular basis. The composite is coded as follows: If all the

indicator variables for regular receipt of relative, nonrelative, and center-based care were equal to “no

regular receipt” and all the indicator variables for ever receiving regular care from a relative, nonrelative,

and center-based program were equal to 2 “no regular receipt ever, ” X1AGCARE is coded as “Not

applicable.” For the remaining cases, if any of the indicator variables for regular receipt of care of any

type was equal to “yes, regular receipt,” or if any of the indicator variables for ever receiving care of any

type was equal to “yes, regular receipt ever,” X1AGCARE is coded as the single youngest age in months

the child first received care of any type. Otherwise, if any of the indicator variables for regular receipt

of care or ever receiving care of any type was equal to “yes,” but the age in months the child first

received care of that type was missing, X1AGCARE is coded as “not ascertained.”

■ Total hours in care [X1HRSCAR] This composite indicates the total number of hours per week

the focal child spent in all primary and secondary care arrangements at the time of the 9-month parent

CAPI instrument. The variable combines hours in child care arrangements in which the child spent the

most time with hours from additional regular child care arrangements.

■ Father in household [X1FTHTYP] As part of providing information on who lives in the household, the household respondent could identify one of the people within the household as the child’s

father, these individuals were located within the household roster, and their relationship to the child

(biological, adoptive, foster, step-, partner of parent, or unknown) was established. For households

containing more than one father, a hierarchy was used to designate the “current” or residential father.

The biological parent, if present, was always the current father. In the absence of a biological parent, the

current father designation was assigned to the adoptive, step-, foster/guardian, partner (including household members defined as spouses/partners of the parent respondent but were not identified by the

respondent as fathers/male guardians), or “unknown-type” parent. If there were no household members that could be identified as one of the father types outlined above, the composite variables were

set to equal 7 (no resident father).

■ When nonresident father last visited child [P1BFLAST]This is an item from the parent interview that asks the respondent, when there is no biological father in the household, when is the last time

the child had contact with their biological father.
30 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Direct Child Assessment, Cognitive and Physical Development

The Bayley Short Form–Research Edition (BSF-R) was used to assess children’s mental (or cognitive) and motor

skills, which is a shortened form of the Bayley Scales of Infant Development–Second Edition (BSID–II).17 Like the

BSID-II, the BSF-R has two scales—a mental scale and a motor (physical development) scale.

■ The mental scale includes items designed to assess early cognitive and language ability. These included

memory, means-end behavior (e.g., ringing a bell to hear a sound), problem solving, concept attainment,

exploration of objects, and preverbal communication (both vocalizations and gestures). Children were

presented with tasks such as putting blocks in a cup, ringing a bell, and responding to a parent’s request

(e.g., peek-a-boo). The main factor assessed by the mental scale is general mental ability. The reliability

of the estimate of the 9-month BSF–R mental scale (IRT-based theta) was .79.

■ The motor scale includes items designed to assess gross and fine motor skills (e.g., picking up objects,

crawling, walking), perceptual-motor integration, and problem solving. Children participated in tasks

such as picking up small objects, grasping a pencil, rolling over from being on their backs, sitting and

standing unsupported, and walking with help. The reliability of the estimate of the 9-month BSF–R

motor scale (IRT-based theta) was .92.

Specific Mental and Motor Skills—Proficiency Level Probability Scores. Proficiency scores provide a means of

distinguishing status in specific skills within a content area from the developmental status measured by the IRT

scale scores. Clusters of two to five test items having similar content and difficulty were included at several

points along the score scale of the BSF–R mental and motor assessments. Clusters of items provide a more

reliable test of proficiency than do single items because of the possibility of children getting the item correct by

chance. The nature of the BSF–R (with basal and ceiling supplements) is that not all children receive all items. To

calculate proficiency estimates for all children, an IRT model was employed. For the purpose of IRT calibration,

the item clusters were treated as single items. The hierarchical nature of the skill sets justified the use of the IRT

model in this way.18

The ECLS–B offers five proficiency levels based on the BSF-R mental scale: (1) explores objects in play, (2)

explores purposefully, (3) babbles, (4) early problem solving, and (5) uses words. Explores objects in play measures

children’s exploration of objects; for example, reaching for and holding objects, but with no specific purpose or

goal except to play or discover. Explores purposefully refers to children’s purposeful exploration of objects; that is,

the child now touches and works with the objects for a reason, such as to seek out what makes the ringing noise

in a bell. Babbles refers to children’s communication through sounds and gestures, and babbling or jabbering. Early

problem solving refers to using reasoning to interact with objects. Uses words measures children’s early verbal

communication using words, both receptive (pointing to named objects) and expressive (saying words).

The ECLS–B offers five proficiency levels based on the BSF-R motor scale: (1) eye-hand coordination, (2) sitting,

(3) prewalking, (4) independent walking, and (5) balance. Eye-hand coordination is children’s ability to grasp and

obtain objects. Sitting refers to children’s mastery at supporting themselves while sitting. Prewalking means that

children demonstrate skills such as taking steps and supporting their weight while standing. Independent walking

measures children’s ability to walk without help from people or holding onto furniture. Balance refers to children’s

ability to balance in various positions (e.g., squatting, standing on one foot).

17Bayley, N. (1993). Bayley Scales of Infant Development, Second Edition Manual. San Antonio, TX: The Psychological Corporation.

18For more information on the BSF-R scale and score formation, see Chapter 3 of the ECLS–B 9-month data file users’ manual [National Center

for Education Statistics (2004). Early Childhood Longitudinal Study, Birth Cohort: 9-month Restricted-Use Data Files User’s Manual (NCES 2004–093).

Washington, DC: National Center for Education Statistics].
31

Appendix B

Standard Error Tables
32 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Table B-2. Standard errors for the percentage distribution of children born in 2001, by

child and family characteristics at time of birth: 2001

Child and family characteristics Population percentage

Total †

Child’s sex

Male 0.09

Female 0.09

Child’s race/ethnicity

White, non-Hispanic 0.52

 Black, non-Hispanic 0.23

Hispanic 0.36

Asian, non-Hispanic 0.10

Native Hawaiian or Other Pacific Islander, non-Hispanic —

American Indian, non-Hispanic 0.06

Multiracial, non-Hispanic 0.27

Birth status

Single 0.01

Twin 0.01

Higher order (e.g., triplet) —

Prematurity (less than 37 weeks gestation)

No 0.42

Yes 0.42

Birth weight

Normal birth weight (more than 5.5 pounds) 0.02

Moderately low birth weight (more than 3.3 to 5.5 pounds) 0.02

Very low birth weight (3.3 pounds or less) 0.01

Child’s mother’s age at child’s birth1

15–17 years 0.19

18–19 years 0.19

20–24 years 0.04

25–29 years 0.03

30–34 years 0.03

35–39 years 0.01

40 years or older 0.02

—Not available, estimate connected to the standard error rounds to zero.

# Rounds to zero.

† Not applicable.

1

Children with mother’s less than 15 years of age were excluded from the study.

NOTE: Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).
Appendix B: Standard Error Tables 33

Table B-3. Standard errors for the percentage distribution of children born in 2001, by

family characteristics at about 9 months of age: 2001

Child and family characteristics Population percentage

Total †

Poverty status

Below poverty threshold 0.60

At or above poverty threshold 0.60

Family type

Married, two biological parents 0.57

Married, two parents 0.09

Cohabiting, two biological parents 0.48

Cohabiting, two parents 0.11

Single parent live alone 0.49

Other (guardian) 0.10

Child’s mother’s education

Less than high school 0.65

High school diploma/GED 0.64

Some college/votech certificate 0.43

Bachelor’s degree or higher 0.30

Child’s father’s education

Less than high school 0.61

High school diploma/GED 0.52

Some college/votech certificate 0.57

Bachelor’s degree or higher 0.52

† Not applicable.

NOTE: Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).
34 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Table B-4. Standard errors for the percentage of children demonstrating specific cognitive

skills, by child’s age at assessment: 2001

Explores Explores Early

objects with problem Uses

Child characteristics in play purpose Babbles solving words

Child’s age at assessment

 8, 9 or 10 months 0.03 0.38 0.41 0.11 —

 8 months 0.06 0.75 0.48 0.08 —

 9 months 0.02 0.31 0.33 0.07 —

 10 months 0.03 0.27 0.53 0.21 0.05

11, 12 or 13 months 0.02 0.14 0.43 0.46 0.25

 11 months 0.04 0.26 0.57 0.49 0.23

 12 months 0.01 0.08 0.63 0.77 0.42

 13 months # 0.05 0.57 0.98 0.66

14 to 22 months 0.01 0.10 0.62 1.47 1.42

—Not available, estimate connected to the standard error rounds to zero.

# Rounds to zero.

NOTE: Children who were assessed at less than 8 months of age (about .4 percent of the sample) are not reflected in this table; however,

unless otherwise noted, are included in the estimates produced in the remainder of the report. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percentage of children demonstrating specific cognitive abilities

Table B-5. Standard errors for the percentage of children demonstrating specific motor

skills, by child’s age at assessment: 2001

Eye-hand Independent

Child characteristics coordination Sitting prewalking walking Balance

Child’s age at assessment

8, 9 or 10 months 0.13 0.13 0.40 0.37 0.04

8 months 0.25 0.28 0.75 0.44 —

9 months 0.16 0.16 0.49 0.41 0.03

10 months 0.13 0.13 0.43 0.63 0.1

 11, 12 or 13 months 0.11 0.08 0.33 1.06 0.50

11 months 0.16 0.13 0.52 1.33 0.36

12 months 0.16 0.12 0.47 1.77 0.95

13 months 0.17 0.12 0.53 1.93 1.34

14 to 22 months 0.09 0.06 0.22 1.04 1.86

—Not available, estimate connected to the standard error rounds to zero.

NOTE: Children who were assessed at less than 8 months of age (about .4 percent of the sample) are not reflected in this table; however,

unless otherwise noted, are included in the estimates produced in the remainder of the report. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Percentage of children demonstrating specific motor abilities
Appendix B: Standard Error Tables 35

Table B-6. Standard errors for the percentage of children participating in child care

around 9 months of age, by primary type of arrangement, and by child and

family characteristics: 2001

Center- No

Relative Nonrelative based Multiple regular

Child and family characteristics care care care arrangements arrangment

 Total 0.69 0.44 0.46 0.13 0.79

Child’s sex

Male 0.85 0.56 0.57 0.17 0.87

Female 0.95 0.63 0.57 0.19 1.20

Child’s race/ethnicity

White, non-Hispanic 0.78 0.65 0.68 0.19 1.20

Black, non-Hispanic 1.48 1.15 1.23 0.37 1.63

Hispanic 1.18 0.84 0.64 — 1.31

Asian, non-Hispanic 1.72 1.07 0.59 — 2.00

Other, non-Hispanic1 2.05 1.95 1.52 0.56 2.53

Mother’s employment status

Full time (35 hours or more) 1.19 0.96 1.03 0.24 0.94

Part time 1.36 1.45 0.80 0.42 1.46

Looking for work 1.89 1.08 1.15 — 1.93

Not in work force 0.62 0.40 0.40 — 0.88

No mother in household 10.26 1.25 8.26 — 8.76

Poverty status

Below poverty threshold 1.20 0.55 0.73 0.15 1.20

At or above poverty threshold 0.73 0.56 0.54 0.13 0.90

—Not available, estimate connected to the standard error rounds to zero.

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Care arrangement
36 Children Born in 2001: First Results From the Base Year of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

Table B-7. Standard errors for the percentage of children in care, percentage of children

by age in months when infants first began child care, and current weekly

hours in all care arrangements, by child and family characteristics: 2001

Younger 3 to 6 More 10 hours More

than 3 months than 6 or fewer 11 to 30 31 to 40 than

Child and family characteristics months months months fewer hours hours 40 hours

Total 1.00 1.20 0.60 0.95 0.86 1.07 0.81

Child’s sex

 Male 1.21 1.24 0.85 1.31 1.12 1.27 0.93

 Female 1.26 1.33 0.95 0.99 1.25 1.41 1.20

Child’s race/ethnicity

 White, non-Hispanic 1.64 1.62 0.92 1.44 1.29 1.50 1.18

 Black, non-Hispanic 1.84 1.74 1.10 1.49 1.17 2.03 1.92

 Hispanic 2.26 2.06 1.15 1.43 1.69 1.71 1.57

 Asian, non-Hispanic 2.35 2.41 1.47 1.54 2.02 2.30 2.22

 Other, non-Hispanic1 2.38 2.80 1.91 2.05 3.48 3.73 2.48

Poverty status

 Below poverty threshold 1.82 2.00 1.16 1.45 1.78 1.88 1.51

 At or above poverty threshold 1.17 1.10 0.69 1.08 1.00 1.22 0.89

Mother’s employment status

 Full time (35 hours or more) 1.29 1.13 0.68 0.93 0.89 1.50 1.18

 Part time 1.99 2.01 1.52 1.80 2.11 1.34 0.97

 Looking for work 2.92 2.62 2.41 2.55 2.81 2.71 2.87

 Not in work force 2.00 2.09 1.74 2.78 2.35 1.90 1.80

 No mother in household 9.79 6.97 10.88 6.69 10.92 13.39 8.50

Primary care arrangement

 Relative care 1.28 1.26 0.89 1.21 1.42 1.24 1.18

 Nonrelative care 1.46 1.59 1.09 1.56 1.50 1.94 1.45

 Center care 2.76 2.56 1.73 1.49 1.52 2.27 2.04

 Multiple arrangements 7.94 7.46 6.14 6.26 6.47 3.01 8.27

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native and Multiracial children.

NOTE: Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Age first began care Total hours in child care arrangement(s)
Appendix B: Standard Error Tables 37

Table B-8. Standard errors for the percentage of children with or without fathers in the

household around 9 months of age, by child and family characteristics: 2001

No father in NonChild and family characteristics household Biological biological

Total 0.50 0.10 0.50

Child’s sex

Male 0.73 0.23 0.68

Female 0.75 0.20 0.75

Child’s race/ethnicity

White, non-Hispanic 0.63 0.24 0.61

Black, non-Hispanic 1.67 0.19 1.65

Hispanic 1.37 0.31 1.30

Asian, non-Hispanic 1.10 — 1.10

Other, non-Hispanic1 2.40 0.50 2.34

Poverty status

Below poverty threshold 1.32 0.30 1.34

At or above poverty threshold 0.46 0.17 0.41

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

—Not available, estimate connected to the standard error rounds to zero.

NOTE: In the absence of a biological parent, the father designation (i.e., nonbiological) was assigned to the adoptive, step, foster/guardian,

partner (including household members defined as spouses/partners of the parent respondent but were not identified by the respondent as

mothers/female guardians or fathers/male guardians), or “unknown-type” parent. Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093) .

Father in household

Table B-9. Of children in households where there is no resident biological father, standard

errors for the percentage of children with contact with their nonresident

biological father, by child and family characteristics: 2001

Visited child More than 2

the same day Visited child Visited child weeks since

as parent in the past 2 in the past 8 last visited Never seen

Child and family characteristics interview to 7 days to 14 days child child

Total 1.42 1.49 0.72 0.45 1.07

Child’s sex

Male 2.04 2.24 1.16 0.70 1.47

Female 1.76 2.22 0.87 0.49 1.49

Child’s race/ethnicity

White, non-Hispanic 2.72 2.67 1.12 0.70 2.01

Black, non-Hispanic 1.63 1.95 1.11 0.70 0.86

Hispanic 3.80 3.42 1.52 0.91 2.62

Asian, non-Hispanic 6.51 8.49 7.40 1.61 6.67

Other, non-Hispanic1 5.66 5.10 2.01 1.03 3.08

Poverty status

Below poverty threshold 1.91 1.77 0.78 0.61 1.23

At or above poverty threshold 1.99 2.17 1.00 0.56 1.51

1

Other includes Native Hawaiian, other Pacific Islanders, American Indian, Alaska Native, and Multiracial children.

NOTE: Estimates weighted by W1R0.

SOURCE: U.S. Department of Education, National Center for Education Statistics, Early Childhood Longitudinal Study, Birth Cohort,

Restricted-Use File (NCES 2004–093).

Nonresident biological father’s contact with child