A Randomized Controlled Trial Evaluating the Impact of Sugar-Sweetened Beverage Health Warnings on Purchases
Phase: NA
Conditions: Dietary Habits
Sponsor: University of North Carolina, Chapel Hill

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Complete Title: Impact of Sugar-Sweetened Beverage Health Warnings  
 
 
Short Title: Impact of Sugar-Sweetened Beverage Health Warnings 
Sponsor: University of North Carolina, Chapel Hill 
Protocol Date: 04/30/2018 
NCT#:  03511937 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sponsor: University of North Carolina, Chapel Hill 
Chapel Hill, NC 27514 
United States 
Study Principal Investigator: Anna H. Grummon 
Department of Health Behavior 
135 Dauer Drive, 302 Rosenau Hall CB 7440 
Chapel Hill, NC 27599 
Phone 650-644-7366 
email: agrummon@unc.edu 
 
 
 
 

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PROTOCOL TITLE:  Impact of Sugar-Sweetened Beverage Health Warnings 
 
Short Title:  
Impact of Sugar-Sweetened Beverage Health Warnings 
 
 
 
 
 
 
 
 
 
 
 
Lead Investigator: 
Anna H. Grummon, MSPH 
 University of North Carolina at Chapel Hill 
Protocol Version: 1.0 
NCT #03511937 
Version Date: April 30, 2018 
 
 
 
 
 
 
 
 
 
I confirm that I have read this protocol and understand it.    
 
Principal Investigator Name:   
Anna H. Grummon 
Principal Investigator Signature:  
 
Date:   
 
 
 
April 30, 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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TABLE OF CONTENTS 
ABBREVIATIONS ................................................................................................................ 4 
PROTOCOL SYNOPSIS ...................................................................................................... 5 
1 
BACKGROUND AND RATIONALE .......................................................................... 7 
2 
STUDY OBJECTIVE................................................................................................... 13 
3 
INVESTIGATIONAL PLAN ...................................................................................... 13 
4 
STUDY PROCEDURES .............................................................................................. 14 
5 
STUDY EVALUATIONS AND MEASUREMENTS ............................................... 16 
6 
STATISTICAL CONSIDERATIONS ........................................................................ 20 
7 
STUDY INTERVENTION .......................................................................................... 25 
8 
SAFETY MANAGEMENT ......................................................................................... 25 
9 
DATA COLLECTION AND MANAGMENT........................................................... 26 
10 RECRUITMENT STRATEGY ................................................................................... 26 
11 CONSENT PROCESS ................................................................................................. 26 
12 REFERENCES ............................................................................................................. 28 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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ABBREVIATIONS  
 
Abbreviation 
Definition 
B-Lab 
Behavioral Lab 
BMI 
Body mass index 
CVD 
Cardiovascular disease 
FOP 
Front-of-package 
OLS 
Ordinary least squares 
SSB 
Sugar-sweetened beverage 
T2D 
Type 2 diabetes 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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PROTOCOL SYNOPSIS 
 
Study Title 
Impact of Sugar-Sweetened Beverage Health Warnings 
Funder 
North Carolina Translational and Clinical Sciences Institute; 
University of North Carolina Department of Family Medicine 
Clinical Phase 
NA 
Study Rationale 
• Sugar-sweetened beverage (SSB) consumption is a major 
contributor to obesity, diabetes, and cardiovascular disease. 
• To reduce SSB consumption, state and local legislators have 
proposed requiring SSB containers to bear front-of-package 
(FOP) labels with health warnings – explicit messages about the 
health harms of consuming SSBs. To date, there are few studies 
assessing whether such warnings influence consumer behaviors.  
• This study aims to evaluate the effect of SSB health warnings on 
sugar-sweetened beverage purchases and secondary outcomes 
using a randomized controlled trial in a naturalistic setting. 
Study Objective(s) 
Primary  
• To evaluate the effect of sugar-sweetened beverage health 
warnings on total calories of sugar-sweetened beverages 
purchased. 
 
Secondary 
• To evaluate the effect of sugar-sweetened beverage health 
warnings on: 
o Number of calories purchased from all foods and 
beverages 
o Proportion of participants who purchased a sugar-
sweetened beverage 
o Number of sugar-sweetened beverages purchased 
o Mean intentions to limit consumption of beverages with 
added sugar 
o Mean intentions to limit consumption of specific sugar-
sweetened beverages 
o Proportion of participants who noticed trial labels 
o Mean attention to trial labels 
o Mean emotional reactions to trial labels 
o Mean cognitive elaboration 
o Social interactions about the trial label 
o Mean perceptions of added sugar content in specific sugar-
sweetened beverages 
o Mean attitudes toward specific sugar-sweetened beverages 
o Mean product attitudes toward specific sugar-sweetened 
beverages 
o Mean outcome expectations regarding consumption of 
sugar-sweetened beverages 

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Test Article(s) 
(If Applicable) 
This study evaluates the effects of exposure to a textual sugar-sweetened 
beverage health warning label compared to exposure to a control label. 
Labels are applied to the the front-of-package of sugar-sweetened 
beverage containers. 
Study Design 
 
Single-center, single-blind, two-arm randomized controlled trial 
evaluating the effects of SSB health warnings.  
Subject Population 
key criteria for 
Inclusion and 
Exclusion: 
Inclusion Criteria 
1. Age 18 and older 
2. Consume at least 1 serving (12 ounces) of sugar-sweetened 
beverages per week 
3. Able to read and write in English 
Exclusion Criteria 
1. Under the age of 18 
2. Consume less than 1 serving (12 ounces) of sugar-sweetened 
beverages per week 
3. Unable to read and/or write in English 
Number of 
Subjects  
400 
Study Duration 
Each subject’s participation will last approximately 30 minutes. 
The enrollment period is expected to last ~6 months. 
Study Phases 
  
There are two phases: 
(1) Screening: screening for eligibility and obtaining consent and  
(2) Intervention: study intervention/experimental treatment. 
Efficacy 
Evaluations 
The primary outcome is the total number of calories from sugar-
sweetened beverages the participant purchases during the study shopping 
task, calculated as the sum of calories/container across all sugar-
sweetened beverages in the participant’s basket at the completion of the 
shopping task.  
Statistical and 
Analytic Plan 
Primary outcome 
• We will use ordinary least squares (OLS) regression to examine 
whether the primary outcome differs by trial arm, controlling for 
any participant characteristics found to be unbalanced across trial 
arms in balance tests. The coefficient on the trial arm indicator 
variable is the primary effect estimate, and gives the average 
difference in (adjusted) means between the treatment arm and the 
control arm. It is interpreted as the impact of SSB health warnings 
on total calories of sugar-sweetened beverages purchased. 
 
Secondary outcomes 
• We will use OLS regression, logistic regression, and Poisson 
regression to examine whether continuous, dichotomous, and 
count secondary outcomes differ by trial arm, respectively. 
Data and Safety 
Monitoring Plan 
• The principal investigator is responsible for data quality 
management and ongoing assessment of safety.   
 
 

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1 
BACKGROUND AND RATIONALE 
Obesity, diabetes, and cardiovascular disease are among the leading causes of death in 
the United States.1 Consumption of sugar-sweetened beverages (SSBs) such as sodas, fruit 
drinks, and sports drinks, is a significant contributor to these preventable conditions.2–6 Despite 
the health risks of SSB consumption, the average American adult drinks a remarkable 40 to 50 
gallons of SSBs every year, accounting for seven percent of daily caloric intake.7–9 To reduce 
SSB consumption, state and local legislators have proposed requiring SSB containers to bear 
front-of-package (FOP) labels with health warnings – explicit messages about the health harms 
of consuming SSBs.10–15 Despite policymakers’ interest in SSB health warnings, there remain 
critical gaps in our knowledge of whether and how such warnings change behavior. 
Theoretical and empirical work suggest that SSB health warnings are a promising 
strategy for reducing consumption. Studies of similar textual health warnings on cigarette packs 
find that warnings reduce smoking in adolescents.16 Likewise, online randomized trials find that 
SSB health warnings reduce intentions to purchase SSBs among adolescents,17 young adults,18 
and parents.19 In turn, intentions strongly predict behaviors,20 and survey research has shown that 
intentions to consume SSBs are associated with actual SSB consumption.21–23 While this 
evidence is suggestive, almost no studies have examined whether SSB health warnings change 
actual behaviors. Answering this question is essential: if effective, SSB health warnings are a 
highly scalable, low-cost intervention that could reduce SSB intake and chronic disease. 
This study aims to evaluate the effects of SSB health warnings on SSB purchases and 
secondary outcomes using a randomized controlled trial in a naturalistic setting.  This Protocol 
and Statistical Analysis Plan is being submitted as an attachment to the study’s trial registration 
(NCT #03511937) prior to analysis. The protocol describes the trial objectives, design, and 
population. The analysis plan pre-specifies planned analyses of the primary, secondary and other 
outcomes, prior to examining the data. In writing the protocol and statistical analysis plan, we 
have adhered to the guidelines set forth by Gamble et al.,24 with minor modifications as needed 
based on trial design.    
 
 
 
 

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1.1 
Introduction 
This is a single-center, single-blind, two-arm randomized controlled trial evaluating the 
effects of SSB health warnings.  
Setting. The trial is conducted in a “mock store” at the Fuqua Behavioral Lab (“B-Lab”), 
located at the Duke Fuqua School of Business in Durham, North Carolina, United States. The B-
Lab mock store was developed for researchers to examine the influence of store and product 
characteristics on consumer behavior in a realistic but controlled environment. The mock store 
resembles a convenience store.  
Products for sale. Beverages for sale in the mock store include a variety of SSBs and 
non-SSBS. To select specific beverages to sell, we examined electronic purchase data25 from 
households in North Carolina to identify popular products by volume purchased in each of the 
following categories of SSBs: sodas; fruit drinks; sports drinks; energy drinks; ready-to-drink 
coffees; ready-to-drink teas; and flavored waters (Table 1). We then identified non-SSBs that 
most closely matched the selected SSBs (e.g., if a particular flavor and brand of soda was 
selected for sale in the store, we also selected the diet version of this soda to sell). For fruit 
drinks, we selected the 100% fruit juices that most closely matched the fruit drink selected (e.g. 
we selected 100% cranberry juice to match the cranberry juice cocktail fruit drink). To more 
fully reflect the beverage retail environment, we also elected to sell plain bottled water and non-
calorically flavored sparkling water, despite these beverages having no corresponding SSB.   
In each beverage category, the store sells at least one variety (i.e., one brand/flavor) of 
the SSB (and therefore at least one variety of the matched non-SSB). We elected to sell five 
varieties of sodas and two varieties of fruit drinks to reflect that more calories of SSBs come 
from these categories than from other SSB categories.26 Beverages are 8.0 to 20.0 fluid ounces 
per container. Non-SSBs are matched to their corresponding SSB in container size.  
Non-beverage items for sale include foods (e.g., chips, crackers, cookies, pre-packaged 
fruits, nuts, canned soups, pasta, cereal, candy) and household products (e.g., shampoo, soap, 
toothpaste, paper towels, notebooks, garbage bags). These products were selected by the B-Lab 
to interest participants and mimic a typical convenience store setting.  
 
 
 

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Table 1. Beverages sold in the trial mock store 
Category 
Sugar-Sweetened Beverage 
Non-Sugar-Sweetened Beverage 
Sodas 
Regular (non-diet) carbonated soft 
drinks and sodas 
Diet carbonated soft drinks and sodas 
Fruit drinks 
Fruit-flavored drinks and juice drinks 
that are not 100% juice 
100% fruit juices 
Sports drinks  
Regular (non-diet) sports drinks 
Diet or low-calorie sports drinks 
Energy drinks 
Regular (non-diet) energy drinks 
Diet or low-calorie energy drinks 
Ready-to-drink 
coffees 
Pre-packaged sweetened coffee 
Pre-packaged unsweetened coffee  
Ready-to-drink 
teas 
Pre-packaged sweetened tea 
Pre-packaged non-calorically 
sweetened tea 
Waters 
Calorically-sweetened flavored 
waters 
Plain (unflavored) waters and non-
calorically sweetened waters 
 
Pricing. To control for the potential influence of price on participants’ purchases, prices 
are held constant across trial arms. Following others,27 we set beverage prices based on standard 
retail prices per ounce in grocery and convenience stores surrounding the laboratory. Prices are 
$1.46 USD for all beverages except for coffees and energy drinks, which are $2.26 USD, 
reflecting their higher retail price. All SSBs and their matching non-SSB were priced identically 
(e.g., regular and diet sodas were the same price; regular and diet energy drinks were the same 
price). Prices for non-beverage items remained at the levels set previously by the B-Lab, which 
had been selected to mimic real-world prices. 
 
1.2 
Description of Trial Arms (Intervention) 
Participants are randomly assigned to one of two arms: a “health warnings” arm 
(intervention) or a control arm. In the health warnings arm, all SSBs are labeled with a health 
warning label. The health warning label is a 1.5” octagon with red background, a white border, 
and white text (Figure 1).  The text reads: “WARNING Beverages with added sugar contribute 
to tooth decay, diabetes, and obesity.” All text is in Arial font. The word “WARNING” is in 12-
point font and the remaining text is in 9.25-point font. The words “WARNING,” “tooth decay,” 
“diabetes,” and “obesity” are bolded.  In the control arm, all SSBs are labeled with a control 
label. The control label is a 1” x 2.625” rectangle label with white background and a black 
barcode image (Figure 1). In both arms, labels are adhered directly on the front-of-package 

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(FOP) of SSB containers. The location of the label on the containers’ packaging is held constant 
across trial arms (i.e., both the health warning label and the control label are placed on the same 
location on the product’s FOP). However, this location on the FOP varies slightly across 
beverage types based on the shape and size of the container.  
 
1.3 
Study Findings (Risk and Benefits) 
Health warnings on SSB are a promising strategy for reducing SSB consumption and the 
associated health risks.  Studies of similar textual health warnings on cigarette packs find that 
warnings reduce smoking in adolescents,16 and pictorial health warnings on cigarettes have been 
shown to increase quit attempts in adults.28 Likewise, online randomized trials find that SSB 
health warnings reduce intentions to purchase SSBs among adolescents,17 young adults,18 and 
parents.19 In turn, intentions strongly predict behaviors,20 and survey research has shown that 
intentions to consume SSBs are associated with actual SSB consumption.21–23 While this 
evidence is suggestive, almost no studies have examined whether SSB health warnings change 
actual behaviors. Answering this question is essential: if effective, SSB health warnings are a 
highly scalable, low-cost intervention that could reduce SSB intake and chronic disease. This 
research will provide timely information on this important gap in our understanding of the effects 
of SSB health warnings.  
Risks of participating in this study are minimal. One risk is that participants may find that 
some questions on the survey make them bored or uncomfortable. To minimize this risk, the 
study duration is short (~30 minutes) and questionnaire items do not query sensitive topics. 
There is also a small risk of loss of privacy resulting from accidental disclosure of study data. 
Figure 1. Health warning label (left) and control label (right) (actual sizes). 

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Not only is this risk small, but the consequences of a rare accidental disclosure would also be 
small, as data collected pertain to beverage consumption, attitudes about beverages, demographic 
characteristics, and choice of products to purchase from a mock store setting. If these data were 
disclosed, they would not affect insurability, social standing, or employment. In this way, data 
collected by the study do not pose any risk greater than what participants encounter in their daily 
life. 
  
1.4 
Relevant Literature and Data 
SSB consumption is a public health problem. On any given day, half of American 
adults consume a sugar-sweetened beverage (SSB),26 and one in seven are considered ‘heavy 
SSB consumers’ (intake > 500 calories/day).29 While some studies have reported declines in 
caloric intake from SSBs since 2003, these declines seem to be leveling off in recent years.8,26 
Further, at more than one serving per day, average SSB consumption among American adults 
remains well above the recommendations set forth in national dietary guidelines.30,31 Across all 
food and beverage categories, SSBs remain the single largest contributor to added sugar intake32 
and are the fourth largest contributor to total caloric intake.33  
These statistics are concerning because SSB consumption has been linked to several 
negative health outcomes including excess body weight, type 2 diabetes (T2D), and 
cardiovascular disease (CVD).2–5,34–38 Among unhealthy foods and beverages, SSBs are often 
singled out as particularly problematic because they are high in calories but offer little or no 
nutritional value,39–41 and because the liquid calories in SSBs cause faster increases in blood 
sugar42 and lower feelings of fullness compared to solid foods.43 Recently, prominent researchers 
have even identified SSBs as perhaps “the single largest driver of the obesity epidemic.”40(p1805) 
Indeed, a meta-analysis of prospective cohort studies estimated that consuming an additional one 
serving (12 ounces) of SSBs per day is associated with a 0.12-0.22 kg increase in weight over the 
course of a year,2 and randomized controlled trials suggest the relationship between SSB 
consumption and weight gain may be even stronger (as high as 2.70 kg/year for an additional 
serving of SSBs/day).38,44  
SSB consumption also increases risk of T2D and CVD, both indirectly via its influence 
on obesity (a known risk factor for poor cardiometabolic outcomes) and directly via its effects on 
metabolic and inflammatory processes.3,4 A recent meta-analysis of prospective studies including 

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more than 310,000 adults found that individuals in the highest quantile of SSB consumption (1-2 
servings/day) had 26% greater risk of developing T2D than those in the lowest quantile (no 
consumption or <1 serving/month).35 In a separate meta-analysis of 17 cohort studies 
representing more than 10 million person-years, Imamura et al. estimated that 8.5% of T2D cases 
in the United States could be attributed to SSB consumption.4 Likewise, data are accumulating to 
suggest that SSB consumption increases risk of cardiovascular problems including hypertension, 
inflammation, adverse lipid profiles, and coronary heart disease.3,45–47  
 
SSB health warnings are a promising policy option for reducing SSB purchases and 
consumption. To reduce SSB consumption and the burden of SSB-related chronic diseases, 
legislators in at least five states and several major cities have proposed requiring SSB containers 
to bear labels with health warnings.10–15 While few studies have examined whether SSB health 
warnings influence consumer behavior, three randomized trials have demonstrated that health 
warnings significantly reduce purchase intentions.17–19 In turn, several theories of health 
behavior, including the Theory of Planned Behavior, posit that intentions are a key determinant 
of behaviors.20,48–50 Cross-sectional studies find that intentions to consume SSBs are positively 
associated with actual SSB consumption among adolescents,22,23 and that intentions to limit SSB 
consumption are negatively related to SSB consumption in adults.21 Together, these studies 
provide support for examining the effects of SSB health warnings on SSB purchases. 
 
SSB health warnings may also influence psychological outcomes. To date, the 
mechanisms through which health warnings influence SSB consumption are largely unknown. 
However, theories of health behavior suggest plausible mediators, including knowledge,51,52 
attitudes,20 and outcome expectations.53–55 Online studies have documented that SSB health 
warnings influence these variables.17,19 Additionally, recent research on pictorial tobacco health 
warnings indicates that three important mediators of the effect of warnings on smoking behavior 
are warning reactions, including attention to the warnings, cognitive elaboration (thinking about 
the warnings), and affective message reactions (fear, worry).56,57 These studies provide support 
for examining the effects of SSB health warnings on psychological outcomes such as knowledge, 
attitudes, outcome expectations, attention, cognitive elaboration, and affective reactions. Specific 
measures this study uses to assess these constructs are described in Section 5 below.  

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2 
STUDY OBJECTIVE  
The primary objective of this trial is to evaluate the effect of SSB health warnings on 
total calories of SSBs purchased. We hypothesize that exposure to SSB health warnings will 
reduce calories of SSBs purchased. The secondary objectives are to evaluate the effect of SSB 
health warnings on the following secondary outcomes: 
• Number of calories purchased from all foods and beverages 
• Proportion of participants who purchased a sugar-sweetened beverage 
• Number of sugar-sweetened beverages purchased 
• Mean intentions to limit consumption of beverages with added sugar 
• Mean intentions to limit consumption of specific sugar-sweetened beverages 
• Proportion of participants who noticed trial labels 
• Mean attention to trial labels 
• Mean emotional reactions to trial labels 
• Mean cognitive elaboration 
• Social interactions about the trial label 
• Mean perceptions of added sugar content in specific sugar-sweetened beverages 
• Mean attitudes toward specific sugar-sweetened beverages 
• Mean product attitudes toward specific sugar-sweetened beverages 
• Mean outcome expectations regarding consumption of sugar-sweetened beverages 
 
 
3 
INVESTIGATIONAL PLAN 
3.1 
Study Design 
This is a single-center, single-blind, two-arm randomized controlled trial evaluating the 
effects of SSB health warnings. The study includes two phases: 
(1) Screening: screening for eligibility and obtaining consent and  
(2) Intervention: study intervention.  
 
 
 

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3.2 
Allocation to Treatment Groups and Blinding 
Participants are randomly assigned to one of two arms: a health warnings arm or a control 
arm. Participants have an equal chance of being randomized to either trial arm (i.e., treatment 
allocation was a 1:1 ratio). An independent biostatistician conducted the randomization prior to 
data collection. Randomization was carried out by generating a random number for each 
participant identification code (ID). Participant IDs were ordered on this random number from 
smallest to largest. The bottom half of the IDs were assigned to the control arm and the top half 
to the treatment arm. This procedure ensures equal group sizes. When participants arrive for their 
study visit, they are assigned the next consecutive participant ID and are allocated to the trial arm 
previously assigned to that ID.   
Participants are blinded to their assigned trial arm. Specifically, they are not told the 
trial’s purpose nor are they told information about the trial arms. The experimenter is aware of 
the trial arm to which the participant has been assigned.   
 
3.3 
Number of Subjects 
This trial aims to enroll 400 participants (200 per arm). See Section 6.4 for information 
on sample size determination. 
 
4 
STUDY PROCEDURES 
4.1 
Screening Procedures 
Eligible participants are English-speaking adults age 18 years or older who consume at 
least one serving (12 ounces) of SSBs per week. Participants must be willing and able to consent 
and comply with study procedures. This study does not employ any exclusions based on race, 
ethnicity, or gender. To determine eligibility, interested participants are asked to complete a brief 
online survey. The survey queries the prospective participant’s age, usual SSB consumption 
(using an adapted version of the BEV-Q 15, a validated questionnaire58), and own and parental 
educational attainment. Participants aged 18 years or older who consume at least 12 ounces of 
SSBs per week are invited to schedule a time to participate. Ineligible participants are thanked 
for their time.  
We will track and summarize participant enrollment, allocation, and analysis using a 
CONSORT diagram. The diagram will report the number of participants who were: 

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• Assessed for eligibility 
• Excluded after screening 
o Excluded because did not meet inclusion criteria 
o Excluded because declined to participate or study visit never scheduled 
o Excluded because cancelled or did not attend study visit 
• Randomized 
• Received allocated intervention (by treatment arm) 
• Analyzed (by treatment arm) 
o Withdrawn and/or excluded from analyses (and reason for exclusion) 
 
4.2 
Experimental Procedures 
The in-person study visit takes place in the Duke Fuqua Behavioral Lab (B-Lab, see 
above description). Participants arrive to the B-Lab at their scheduled appointment time and are 
greeted by the experimenter. After providing informed consent (see Section 11 below), 
participants are escorted to the mock store. When they arrive in the mock store, they are provided 
with a shopping basket and their participation incentive ($10 USD) in cash. SSBs in the mock 
store are pre-labeled with the appropriate label based on the participant’s assigned trial arm 
(health warning vs. control). Participants are instructed to pretend they are on a usual shopping 
trip and reminded that there are no right or wrong products to select. They are not told the trial’s 
purpose nor are they told information about the trial arms.   
Participants are asked to complete a shopping task. They are given a list of three product 
categories (household items, foods, and beverages, listed in this order) and are asked to select 
two items in each of these categories, for a total of six items. They indicate their selections by 
placing items in their shopping basket. Participants are instructed that, within each category, they 
can select the same item twice, or can select two different items (e.g., can select the same food 
item twice, or select two different food items). Participants are then instructed that they will be 
required to purchase one of the items they select, and that this item will be chosen for them at 
random by the experimenter. This procedure incentivizes participants to only select products 
they are actually interested in purchasing. The experimenter ensures the participant understands 
the instructions then leaves the mock store while the participant completes the shopping task.  
After participants have completed the shopping task, the experimenter records what 

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products are in the participant’s basket, then randomly selects one of the products for the 
participant to purchase with his or her incentive cash. The participant pays for the product and 
receives change as necessary. After paying for their item, the participant completes a computer-
based survey in another room. 
 
4.3 
Withdrawal Procedures 
Individual participants will be withdrawn from the study if they indicate they do not wish 
to participate (i.e., refuse or withdraw their consent), or if they cannot comply with the study 
procedures, such as not arriving at the laboratory to complete the shopping task or not being 
willing to select products in the mock store.  
 
5 
STUDY EVALUATIONS AND MEASUREMENTS  
Outcome variables, organized by type (i.e., primary, secondary, other), are described in 
Table 2. Purchase variables (i.e., number of calories purchased from SSBs, number of calories 
purchased from all foods and beverages, proportion of participants who purchased an SSB, and 
number of SSBs purchased) are assessed by the experimenter, who records all of the 
participant’s selections at the end of the shopping task. All other outcomes are assessed via 
participant self-report on a computer-based survey that is completed within ~30 minutes of 
completing the ~10-minute shopping task. 
Table 2. Outcome variables. 
Outcome 
Definition/Description 
Timing of 
Assessment 
Primary Outcome 
Number of 
calories (kcal) 
purchased 
from SSBs 
Total number of calories from sugar-sweetened 
beverages in the participant’s basket when he/she 
completes the shopping task, calculated as the sum of 
calories/container for all SSB containers. 
Immediately after 
the participant 
completes the 
~10-minute 
shopping task. 
Secondary Outcomes 
Number of 
calories (kcal) 
purchased 
from all foods 
and beverages. 
Assessed as the total number of calories from all 
products (including sugar-sweetened beverages, non-
sugar-sweetened beverages, and all foods) in the 
participant’s basket when he/she completes the shopping 
task. Total calories purchased will be calculated as the 
sum of calories/container for all products. 
Immediately after 
the participant 
completes the 
~10-minute 
shopping task. 

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Outcome 
Definition/Description 
Timing of 
Assessment 
Proportion of 
participants 
who purchased 
a sugar-
sweetened 
beverage 
Assessed as the proportion of participants who have one 
or more sugar-sweetened beverage in his/her basket 
when he/she completes the shopping task.  
 
Immediately after 
the participant 
completes the 
~10-minute 
shopping task. 
Number of 
sugar-
sweetened 
beverages 
purchased 
Assessed as the number of sugar-sweetened beverages in 
the participant’s basket when he/she completes the 
shopping task.  
Immediately after 
the participant 
completes the 
~10-minute 
shopping task. 
Mean 
intentions to 
limit 
consumption 
of beverages 
added sugar 
Assessed using 3 items adapted from Klein, Zajax & 
Monin (2009).59 The items ask participants to rate the 
extent to which they want to, plan to, and are likely to, 
drink less than 1 beverage with added sugar in the next 
week. Responses to these three items will be averaged to 
create a mean intentions score. Response options are on a 
1 to 7 scale, with higher scores indicating higher 
intentions to limit consumption of beverages with added 
sugar. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean 
intentions to 
limit 
consumption 
of specific 
sugar-
sweetened 
beverages 
Assessed using 5 items adapted from Klein, Zajax & 
Monin (2009).59 For each of the five beverage categories, 
participants will rate the extent to which they are likely 
to drink less than 1 serving of the beverage in the next 
week. Responses will be averaged to a create a mean 
intentions score. Response options are on a 1 to 7 scale, 
with higher scores indicating higher intentions to limit 
consumption of these beverages. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Proportion of 
participants 
who notice the 
trial labels 
Assessed using 1 item adapted from Roberto et al. 
(2016).19 The item asks participants to indicate whether 
they noticed the trial labels. Response options are 0 (no) 
and 1 (yes). 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean attention 
to the trial 
labels 
Assessed using 2 items adapted from Nonnemaker et al. 
(2010).60 The items ask participants to rate their 
agreement with statements about whether the label 
grabbed their attention and whether they read and looked 
closely at the label. Responses will be averaged to create 
a mean attention score. Responses are on a 1 to 5 scale, 
with higher scores indicating higher attention to the 
labels. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 

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Outcome 
Definition/Description 
Timing of 
Assessment 
Mean 
emotional 
reactions to 
trial labels 
Assessed using 6 items adapted from Brewer et al. 
(2018).61 The items ask participants to indicate the extent 
to which trial labels elicited particular emotional 
reactions (e.g., fear, guilt, disgust). Responses will be 
averaged to create a mean emotional reactions score. 
Response options are on a 1 to 5 scale, with higher scores 
indicating stronger emotional reactions. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean 
cognitive 
elaboration 
Assessed using 2 items adapted from Moodie, 
MacKintosh & Hammond (2010)16 and Fathelrahman et 
al. (2010).62 Items ask participants to rate the amount 
they thought about the information conveyed by the trial 
label and about the health consequences of consuming 
beverages with added sugar. Responses will be averaged 
to create a mean cognitive elaboration score. Response 
options range from 1 to 5, with higher scores indicating 
more elaboration. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Social 
interactions 
about the 
labels 
Assessed using 1 item adapted from Brewer et al. 
(2018).61 Participants rate the extent to which they are 
likely to have social interactions about the trial label. 
Response options are on a 1 to 5 scale, with higher scores 
indicating a higher likelihood of having social 
interactions. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean 
perceptions of 
added sugar 
content in 
specific sugar-
sweetened 
beverages 
Assessed using 5 items adapted from Roberto et al. 
(2016).19 For each of five beverage categories, 
participants rate the amount of added sugar they think is 
in 1 serving of the beverage. Responses will be averaged 
to create a mean perceptions of added sugar score. 
Response options are on a 1 to 4 scale, with higher scores 
indicating perceptions of higher added sugar content. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean attitudes 
toward 
consuming 
specific sugar-
sweetened 
beverages 
Assessed using 5 items adapted from Bollard et al. 
(2016).18 For each of five beverage categories, 
participants rate how healthy/unhealthy it is for them to 
consume that beverage category. Responses will be 
averaged to create an mean attitudes score. Response 
options are on a 1 to 7 scale, with higher scores 
indicating more positive attitudes toward consuming 
these sugar-sweetened beverages. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 

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Outcome 
Definition/Description 
Timing of 
Assessment 
Mean product 
attitudes 
toward specific 
sugar-
sweetened 
beverages 
Assessed using 10 items adapted from Bollard et al. 
(2016).18 For each of five beverage categories, 
participants rate the appeal and the coolness of the 
beverage category. Responses will be averaged to create 
a mean product attitude score. Responses are on a 1 to 7 
scale, with higher scores indicating more positive 
product attitudes toward these sugar-sweetened 
beverages. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean outcome 
expectations 
regarding 
consumption 
of beverages 
with added 
sugar 
Assessed using 4 items adapted from Roberto et al. 
(2016).19 Participants will rate the extent to which they 
expect that consuming beverages with added sugar would 
increase their risk of negative health outcomes (e.g., 
tooth decay). Responses will be averaged to create a 
mean outcome expectations score. Responses are on a 1 
to 7 scale, with higher scores indicating more negative 
outcome expectations. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Other Outcomes 
Mean 
injunctive 
norms 
regarding 
consumption 
of beverages 
with added 
sugar 
Assessed using 3 items adapted from Zoellner et al. 
(2012).21 Items ask participants to rate the extent to 
which people who are important to them think they 
should drink less than 1 beverage with added sugar per 
week, would approve of them drinking less than 1 
beverage with added sugar per week, and want them to 
drink less than 1 beverage with added sugar per week. 
Responses will be averaged to create a mean injunctive 
norms score. Responses are on a 1 to 5 scale, with higher 
scores indicating higher injunctive norms. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Perceived 
message 
effectiveness 
of trial label 
Assessed using 1 item adapted from Brewer et al. 
(2018).60 Participants rate the extent to which the trial 
label to which they were exposed in the shopping task 
would discourage them from drinking beverages with 
added sugar. Response options are on a 1 to 5 scale, with 
higher scores indicating higher perceived message 
effectiveness. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Support for 
sugar-
sweetened 
beverage 
health warning 
labels 
Assessed using 1 item adapted from Brewer et al. 
(2018).60 Participants rate their support for a policy that 
would require health warning labels on sugar-sweetened 
beverages. Responses are on a 1 to 4 scale, with higher 
scores indicating greater support. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 

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Outcome 
Definition/Description 
Timing of 
Assessment 
Mean self-
efficacy to 
limit 
consumption 
of beverages 
with added 
sugar 
Assessed using 3 items adapted from Brewer et al. 
(2018).60 Items ask participants to rate the extent to 
which: it would be easy to drink less than 1 beverage 
with added sugar per week; they have the ability to drink 
less than 1 beverage with added sugar per week; and they 
are confident that they could drink less than 1 beverage 
with added sugar per week. Responses will be averaged 
to create a mean self-efficacy score. Responses are on a 1 
to 5 scale, with higher scores indicating self-efficacy. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
Mean response 
efficacy of 
limiting 
consumption 
of beverages 
with added 
sugar 
Assessed using 5 items adapted from Brewer et al. 
(2018).60 Participants indicate the extent to which 
drinking no beverages with added sugar would lower 
their chances of weight gain, diabetes, tooth decay, and 
heart disease, and the extent to which drinking no 
beverages with added sugar would improve their health. 
Responses will be averaged to create a mean response 
efficacy score. Responses are on a 1 to 5 scale, with 
higher scores indicating greater response efficacy. 
Within 30 
minutes of 
completing ~10-
minute shopping 
task 
 
6 
STATISTICAL CONSIDERATIONS    
General principles and analysis populations. We will use a two-sided critical alpha of 
0.05 to conduct all statistical tests. All confidence intervals presented will be 95% and two-sided. 
Analyses of the primary, secondary, and other outcomes will include all randomized participants 
according to the trial arm they were randomized to receive. We will use complete case analysis 
to handle any missing data in analyses of the primary, secondary, and other outcomes.      
 
6.1 
Primary Endpoint 
The primary outcome variable is the total number of calories from sugar-sweetened 
beverages the participant purchased during the shopping task (see also Table 2).  
 
6.2 
Secondary Endpoint 
Secondary outcomes are listed in Table 2.  
 
 
 

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6.3 
Statistical Methods 
Data preparation and balance tests. To prepare the data, we will first examine all 
scales to ensure adequate internal consistency (i.e., Cronbach’s alpha > 0.70), dropping items as 
needed to improve consistency. If we are unable to achieve adequate internal consistency by 
dropping items, we may exclude the unreliable scales from analyses (e.g., not analyze treatment 
effects on these outcomes).  
Next, we will conduct balance tests. Specifically, we will report participants’ age, gender, 
sexual orientation, Hispanic ethnicity, race, educational attainment, health literacy, household 
income, usual sugar-sweetened beverage consumption, and overweight status (body mass index 
[BMI] ≥ 25 kg/m2) by trial arm. We will summarize categorical variables as counts and 
percentages and continuous variables as means and standard deviations. The denominator for 
each percentage will be the number of participants within each treatment group, less any 
participants with missing data on the variable of interest. We will use t-tests and χ2 tests to 
examine whether participants assigned to the trial arms differ on any continuous or categorical 
characteristics, respectively. We will report p values from these balance tests. Subsequent 
analyses will control for any unbalanced characteristics.  
 
Analysis of the primary outcome (Efficacy analysis). We will use ordinary least 
squares regression (OLS) to examine whether the primary outcome differs by trial arm. 
Specifically, we will fit the following: 
𝑆𝑆𝐵 𝑐𝑎𝑙𝑜𝑟𝑖𝑒𝑠 𝑝𝑢𝑟𝑐ℎ𝑎𝑠𝑒𝑑= 𝛽0 +  𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+  𝑋𝛽  
 
(Eq. 1) 
Here, SSB calories purchased is the total calories from SSBs the participant had in her basket 
when she completed her shopping task, calculated as described in Table 2. WARNING is an 
indicator variable for whether the participant was in the health warning arm (WARNING = 1) or 
the control arm (WARNING = 0). We denote 𝑋 as a vector of any participant characteristics 
(e.g., age, gender, race/ethnicity) found to be unbalanced across trial arms in balance tests.  
The coefficient on WARNING (𝛽1) is the primary effect estimate, and gives the average 
difference in (adjusted) means between the treatment arm and the control arm. It is interpreted as 
the impact of SSB health warnings on total calories of SSBs purchased.  
Planned exploratory analyses of the primary outcome. We will examine whether the 
following participant characteristics moderate (modify) the effect of SSB health warnings on 
SSB purchases:  

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a) Age category (18-29, 30-39, 40-54, and 55 years or older); 
b) Sex (male vs. female); 
c) Sexual orientation (gay, lesbian, or bisexual vs. not); 
d) Race/ethnicity (white vs. non-white);  
e) Low educational attainment (some college or less vs. college or more),  
f) Limited health literacy (possibility or high likelihood of limited literacy vs. adequate 
literacy, based on score on the Newest Vital Sign63,64);  
g) Household income ($50,000 or more vs. less than $50,000); 
h) Usual SSB consumption (above vs. at or below the sample median); 
i) Overweight status (BMI ≥ 25 kg/m2 vs. BMI < 25 kg/m2); 
 
To test whether these characteristics moderate the effect of SSB health warnings on SSB 
purchases, we will fit a series of regressions (one for each potential moderator) taking the 
following general form: 
𝑆𝑆𝐵 𝑐𝑎𝑙𝑜𝑟𝑖𝑒𝑠 𝑝𝑢𝑟𝑐ℎ𝑎𝑠𝑒𝑑= 𝛽0 +  𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+ 𝛽2𝐶𝐻𝐴𝑅𝐴𝐶𝑇𝐸𝑅𝐼𝑆𝑇𝐼𝐶 +
 𝛽3(𝑊𝐴𝑅𝑁𝐼𝑁𝐺∗𝐶𝐻𝐴𝑅𝐴𝐶𝑇𝐸𝑅𝐼𝑆𝑇𝐼𝐶) +  𝑋𝛽    
 
 
 
 
 
(Eq. 2) 
Here, SSB calories purchased, WARNING, and 𝑋 are as defined previously and 
CHARACTERISTIC is the moderator variable (e.g., an indicator for low educational 
attainment). Moderation is present if 𝛽3 is statistically significant. We will probe significant 
interactions by calculating the marginal effect of health warnings on SSB calories purchased at 
different levels of the moderating variable.   
Analysis of the secondary outcomes. We will use different analytic approaches to assess 
whether secondary outcomes differ by trial arm, depending on the level of measurement of the 
secondary outcome (i.e., continuous, count, or dichotomous).  
The following secondary outcomes are continuous will be assessed using OLS 
regression: 
• Number of calories purchased from all foods and beverages 
• Mean intentions to limit consumption of beverages with added sugar 
• Mean intentions to limit consumption of specific sugar-sweetened beverages 
• Mean attention to trial labels 

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• Mean emotional reactions to trial labels 
• Mean cognitive elaboration 
• Social interactions about the labels 
• Mean perceptions of added sugar content in specific sugar-sweetened beverages 
• Mean attitudes toward consuming specific sugar-sweetened beverages 
• Mean product attitudes toward specific sugar-sweetened beverages 
• Mean outcome expectations regarding consumption of beverages with added sugar 
These regressions will take the general form of: 
𝑌= 𝛽0 +  𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+  𝑋𝛽   
 
 
 
 
(Eq. 3) 
Here, WARNING and 𝑋 are as defined previously and Y is the continuous secondary outcome. 
As above, the effect estimates are given by the coefficient on WARNING (𝛽1). This coefficient 
gives the average difference in (adjusted) means between the treatment arm and the control arm; 
it is interpreted as the impact of SSB health warnings on the secondary outcome being examined.  
One of the secondary outcomes, number of SSBs purchased, is a count variable (i.e., 
takes on only nonnegative integer values) and is thus better evaluated with a count data model. 
To examine number of SSBs purchased, we will begin by fitting a Poisson regression: 
𝑃𝑟𝑜𝑏(𝑦|𝜆) = 
𝑒−𝜆𝜆𝑦
𝑦!    for y=0,1,2 
 
 
 
 
(Eq. 4) 
where 
𝜆= 𝑒(𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+ 𝑋𝛽 ) 
 
 
 
 
(Eq. 5) 
WARNING is an indicator for treatment arm, 𝑋 is a vector of any unbalanced participant 
characteristics and 𝑦 is the observed number of SSBs purchased. Following the advice of 
Kennedy,65 we will use robust standard errors to address the potential for overdispersion. We 
will test model fit using the Pearson goodness-of-fit test;66 if the null hypothesis of a Poisson 
distribution is rejected, we will use a negative binomial regression in place of a Poisson 
regression. In either case, we will report the average differential effect of being in the health 
warning arm (vs. being in the control arm) on the predicted number of SSBs purchased. 
Finally, the following secondary outcomes are dichotomous and will be assessed using 
logistic regression: 

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• Purchase of a sugar-sweetened beverage 
• Noticing of the trial labels  
These regressions will take the general form of: 
𝑃𝑟𝑜𝑏(𝑌= 1|𝑊𝐴𝑅𝑁𝐼𝑁𝐺, 𝑋) = 
𝑒(𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+𝑋𝛽)
1+𝑒(𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+𝑋𝛽)  
 
 
(Eq. 6) 
WARNING and 𝑋 are as defined previously, and Y is the dichotomous secondary outcome. For 
logistic regression results, we will report the average differential effect of being in the health 
warning arm (vs. being in the control arm) on the probability of the outcome occurring (i.e., 
probability the participant purchased a sugar-sweetened beverage), calculated using the method 
of recycled predictions.66 
Analysis of other outcomes. We will use OLS regression to examine differences by trial 
arm in the following other outcomes (all of which are continuously measured): 
• Mean injunctive norms regarding consumption of beverages with added sugar 
• Perceived message effectiveness of trial label 
• Support for sugar-sweetened beverage health warning labels 
• Mean self-efficacy to limit consumption of beverages with added sugar 
• Mean response efficacy of limiting consumption of beverages with added sugar 
To examine these outcomes, we will fit linear regressions of the general form: 
𝑌= 𝛽0 +  𝛽1𝑊𝐴𝑅𝑁𝐼𝑁𝐺+  𝑋𝛽   
 
 
 
 
(Eq. 7) 
WARNING and 𝑋 are as defined previously and Y is the continuous other outcome. As above, 
the effect estimates are given by the coefficient on WARNING (𝛽1). This coefficient gives the 
average difference in (adjusted) means between the treatment arm and the control arm; it is 
interpreted as the impact of SSB health warnings on the outcome being examined.  
Statistical software. Data preparation and analyses will be conducted in Stata Version 
15.1 (StataCorp LLC, College Station TX).  
 
6.4 
Sample Size and Power 
The primary objective of this trial is to evaluate the effect of SSB health warnings on 
total calories of SSBs purchased. We used G*Power3 to determine sample size needs for 

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addressing this objective.67 At the time of sample size determination, no studies of SSB health 
warnings had examined behavioral outcomes. Thus, we drew on effect sizes from studies of 
warnings’ impact on intentions to purchase SSBs. These studies report medium17,19 or large18 
effect sizes. To account for the intention-behavior gap, we powered the trial to detect an effect 
size between small and medium (standardized Cohen’s 𝑓2 = 0.02, i.e., trial arm will explain 2% 
of the total variance in SSB purchases).68–70 Using these specifications and a two-sided alpha of 
0.05, we determined a necessary sample of 395 to detect an effect of 𝑓2 = 0.02 or larger with 
80% power. To account for potential missing data or incomplete study visits, we aimed to enroll 
400 participants (200 in each arm).  
 
6.5 
Interim Analysis 
 
No interim analyses were planned.  
 
7 
STUDY INTERVENTION 
The intervention is exposure to a textual sugar-sweetened beverage health warning label. 
The health warning label is a 1.5” octagon with red background, a white border, and white text, 
as described in Section 1.2 above. In the health warnings arm, SSB health warning labels are 
adhered directly to the front-of-package of all SSB containers in the mock store.  
 
8 
SAFETY MANAGEMENT 
 
To ensure the safety of participants, the principal investigator will monitor all data, 
including answers to free response survey questions, throughout the data collection period. No 
adverse events or medical emergencies are anticipated, as participants are completing 
questionnaires and completing normal activities of daily living (selecting products at a small 
store). Further, given the very low-risk nature of the study, there were no a priori criteria for 
stopping the entire study prematurely due to safety concerns or unexpected adverse events. The 
PI will monitor for any adverse events or medical emergencies and promptly report these to the 
sponsoring IRB following standard reporting procedures.  
 

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9 
DATA COLLECTION AND MANAGMENT  
 
Participant confidentiality will be protected throughout all phases of the research, 
including data collection, analysis, and publication of results. Other than to schedule participants 
for their study visit (for which contact information must be collected), this study does not collect 
any identifying information.  All data (responses to survey questions, product selections made 
during the experiment) will be de-identified (i.e., will only be attached to identification codes, 
and not to any identifiable information). The key linking identification codes and respondent 
information will be kept in a locked file cabinet in a locked office and on a secure, password-
protected computer/server. The key will be destroyed after data collection is complete.  
 
10 
RECRUITMENT STRATEGY 
This study aims to recruit a convenience sample of 400 adults through a variety of 
methods our team has used to recruit diverse samples,71 including via community subject pools 
at the University of North Carolina, Chapel Hill (UNC) and Duke University, printed flyers 
posted in campus and community venues and distributed in-person on UNC and Duke campuses, 
and online advertisements on sites such as Craigslist and Facebook. Individuals who are 
interested in learning more about the study are invited to complete an online screening 
questionnaire. The screening questionnaire assesses the prospective participant’s age, usual SSB 
consumption (using the BEV-Q 15, a validated questionnaire57), and own and parental 
educational attainment. Eligible participants are English-speaking adults at least 18 years old 
who consume at least 12 ounces of SSBs per week.57 Eligible potential participants will be 
invited to schedule a time to participate. Ineligible participants will be thanked for their time.  
 
11 
CONSENT PROCESS 
This study obtains informed consent separately for the pre-enrollment screening 
questionnaire (screening phase) and for the in-person study visit (intervention phase).  
For screening questionnaire, this study obtains informed consent via an online consent 
form with electronic agreement. The online consent form is presented to participants before they 
begin the online screening questionnaire. Participants are asked to read the form and indicate 
whether they agree to participate in the research. If they agree to participate, they select a button 

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labeled “I consent” and proceed with the survey. If they do not agree, the survey is ended and no 
information is collected.   
For the in-person study visit, this study obtains written informed consent. When 
participants arrive for their study visit, the experimenter (the PI or a trained research assistant) 
escorts them to a private study room in the lab suite. The participant is provided with a copy of 
the consent document. The experimenter reviews the consent document with the participant and 
answers any questions the participant has. The document the general nature of the study, the 
risks and benefits of the study, and the general procedures used. After reviewing the document 
with the experimenter and asking any questions she may have, the participant indicates whether 
she agrees to participate. If the participant agrees to participate, both she and the experimenter 
sign and date a copy of the consent document. If the participant declines to participate, she is 
thanked and the study visit is ended.  
The consent form for the in-person study visit uses incomplete disclosure. Specifically, 
the consent document gives general information about the study purpose (i.e., “a study about 
how consumers make choices in a naturalistic store setting") but does not provide enough detail 
to reveal the main study objective. Participants are given truthful information about the study 
procedures in general terms (i.e., that they will be asked to select items in a shopping task and to 
complete a survey about their experience the store, attitudes and beliefs, and personal 
characteristics), including truthful information about the risks and benefits of participating in the 
study, but are not be fully informed about the study’s expected findings. After completing the 
study visit, participants are provided with a “Debriefing” form that provides details about the 
nature and purpose of the study. They are also given the opportunity to ask any questions they 
have about the study.  
 
 

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12 
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