Relationship of Collected Data to Study Objectives

APPENDIX A

RELATIONSHIP OF COLLECTED DATA TO STUDY OBJECTIVES

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RELATIONSHIP OF COLLECTED DATA TO STUDY OBJECTIVES
ERS’s stated mission is to anticipate economic and policy issues related to agriculture, food, the
environment, and rural development, and conduct economic research that broadly and specifically
informs public program and policy decisions. To support this mission, ERS is sponsoring the National
Food Study to collect information that will meet a variety of research needs, including estimating
household food demand systems and understanding the role of food assistance programs in influencing
food choice, food expenditures, and food security.
Individual and household demand for food (generally) and individual food items (specifically) results
from a complicated interplay of many different factors, including:
attributes (e.g., nutrients, taste) of the food product being considered
the food product’s price;
the price and attributes of similar foods (possible substitutes);
the price and attributes of complementary foods (e.g., cheese with crackers);
one’s income and wealth;
one’s knowledge about nutrition and diet;
the presence of food allergies;
one’s perceptions of his or her health, especially with regard to weight and health risks
associated with obesity;
time available to prepare meals at home;
the stocked food items at stores conveniently accessible; and
the presence of nearby restaurants offering a variety of menus and prices.
For persons shopping for a household, the preferences of other household members also impact household
demand for food.
The planned data collection involves multiple instruments and sources in order to efficiently capture the
many elements needed to understand and statistically model the overall household demand for food. To
begin, the National Food Study will collect information on foods acquired for consumption by all
household members both at home (FAH) and away from home (FAFH) because households have a choice
whether to, say, prepare meals at home or go out to a restaurant. The survey will also collect information
on foods acquired for free (e.g., vegetables from the garden, food from Food Banks, meals eaten at the
homes of friends or relatives) as well as those purchased. Information on food prices and total household
income will be collected to estimate the proportion of household income spent on food versus non-food
items, on FAH versus FAFH, and by food group (e.g., proportion of total food budget spent on fruits and
vegetables). Collected data on prices and total income will enable estimation of the income and price
elasticities of food. This detailed information is vital to support ERS’s mission to inform public program
and policy decisions.
To better understand the role of food assistance programs in influencing food choice, food expenditures,
and food security, the National Food Study will collect information from participants in the nation’s
largest food assistance program, the Supplemental Nutrition Assistance Program (SNAP) as well as from
low-income households that choose not to participate in SNAP. ERS is interested in understanding how
household demand differs between these two low-income groups as well as between lower- and higherincome households.
This appendix contains two tables. Table A1 presents the study’s research objectives and identifies which
data sources provide information needed to address each objective.

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Table A1. Relationship of Collected Data to Study Objectives
Data Source
Study Objective
1. Describe the food and beverage purchases and acquisition patterns of the population universe and
subgroups.
a. What food items do household members acquire from
the following sources:
Food book, scanner data
i. Purchases from food retailers primarily for preparation
and consumption at home (FAH), and
Food books, telephone reporting of foods-away-fromii. Purchases of prepared foods and beverages from food home
service establishments (e.g., restaurants, cafeterias, and
vending machines primarily for consumption away from
home (FAFH) (e.g., meals at restaurants, unsubsidized
school meals, snacks or beverages from vending
machines)?
b.

What are the quantities and purchase prices (or implicit
values) of the above foods, snacks, and meals? Measures
will include:
i. Sources, quantities, and prices of items purchased
ii. Sources and quantities of non-priced items that are
acquired

For FAH, the scanner captures item quantities and
scanned barcodes are mapped to item package sizes.
Prices are added from receipts, Nielsen price files, or
imputed values.

What non-priced food items do household members
acquire for consumption either at home or away from
home? What are the quantities and sources (e.g., food
pantries, emergency kitchens, Meals-on-Wheels, home
gardens or farms, fishing and hunting trips, gifts,
compensation for work, meals at the homes of family or
friends) of these foods and beverages?

For FAH, the scanner captures items, quantities, and
the source is recorded in the food book (blue page).

d.

How are these foods characterized in terms of food
groups and subgroups (including units of USDA food
pyramid groups: grains, vegetables, fruits, milk, meat
and beans, oils)?

Mathematica will map UPCs and FAFH acquisitions to
food groups, utilizing the food groupings in the UPC
data dictionary and building on food group schema
developed on other USDA projects to apply to USDA
food codes.

e.

For each household member, what purchase/acquisition
occasions occur during each day of the reporting period?

Acquisitions will be reported in food books (Daily
Lists, Blue pages, Red Pages).

f.

For each household member (or guest), what meals and
snacks (i.e., breakfast, morning snack, lunch, afternoon
snack, dinner, evening snack, and other) are consumed
each day of the reporting period?

Meals and snacks will be reported on the Meals and
Snacks Form.

g.

For questions a through f above, how do the food
acquisition patterns vary by population group (e.g.,
SNAP households, nonparticipating low-income
households, and higher-income households)?

Households are asked about SNAP participation in the
screener. SNAP participation will be validated by a
match to administrative data, for households
providing consent for an administrative data match.

h.

How do food acquisition patterns (e.g., days of week
when household members obtain subsidized school
lunches) and funding sources (e.g., cash, credit, SNAP
benefits via EBT card, WIC food instruments) for
purchased items vary throughout the month in
relationship to when program benefits and/or other
income are received?

Food books capture total purchase amount and
funding source; receipts will be used to fill missing
data and for quality control. Timing of food assistance
benefit receipt is asked during Initial Household
Interview and confirmed by SNAP administrative data.

i.

What are average weekly food expenditures? What share
of average weekly household expenditures do food costs
represent? How are weekly food expenditures allocated
across food groups and subgroups? How do these
measures vary by population group?

Average weekly food expenditures will be calculated
from information reported in food books for FAH and
FAFH, overall and by food group and subgroup.
Average weekly non-food expenditures will be
calculated from information collected in the Final
Household Interview.

c.

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For FAFH, quantities and prices are recorded in food
books and/or indicated on receipts and reported
during the telephone reporting of FAFH.

For FAFH, items and quantities are recorded in food
books (red page) and reported during the telephone
reporting of FAFH.

Table A1 (continued)

Study Objective
1-j What proportion of low-income households not
participating in SNAP are likely to be program eligible
based on their gross and net income and resources?
How do these households compare to SNAP households
in terms of weekly food expenditures, food acquisition
and nutrition patterns, and food security?

Data Source
Food books and receipts capture what foods are
acquired, where food is acquired, food quantities
and prices. Income, resource, and expenditure
information to estimate SNAP eligibility collected by
Final Household Interview.

2. Characterize the nutritional quality of households’ food purchases and acquired food.
a.

Considering all sources of food acquisition, characterize
the food choices and nutritional quality of households’
acquired foods. What are the differences in USDA
pyramid food group units and nutritional quality
between food purchased primarily for at home (FAH)
versus away from home (FAFH) consumption?

Acquired food items will be matched with nutrient
data from USDA’s Standard Reference Database
(SR21). MyPyramid units will be merged by SR21
food codes.

b.

How do these measures vary by population group (e.g.,
SNAP households, nonparticipating low-income
households, and higher-income households)?

Above analyses by population group.a

c.

How do these measures vary between SNAP households
and eligible but nonparticipating households?

Acquired food items will be matched with nutrient
data from USDA’s Standard Reference Database
(SR21). MyPyramid units will be merged by SR21
food codes. Income, resource, and expenditure
information to estimate SNAP eligibility collected by
Final Household Interview.

3. Characterize the nature of food access of the population universe and groups.
a.

Where do respondents shop for food (type of
source/vendor and geographic proximity to household),
and how do decisions about where to shop vary by
household characteristics? How do decisions about
where to shop vary by time of month relative to program
issuance dates and/or pay dates? Do shopping choices
of population groups vary and, if so, how?

FAH shopping locations are reported in the food
books (Daily List and Blue pages) and observed on
receipts. The exact location of usual shopping
locations is collected during Initial Household
Interview, along with travel modes and travel cost.
Geographic distance will be calculated as driving
distance from respondents’ homes to usual
shopping locations.
FAFH locations are reported in food books (Daily List
and Red pages) and reported and confirmed during
telephone interviews. Geographic distance will be
calculated as driving distance from respondents’
homes.

b.

How long does it take for shoppers to travel to their
main food stores? What mode(s) of transport do they
use? What costs (time and out-of-pocket) do households
in the sample incur when they shop for food?

c.

For both SNAP participants and nonparticipants, in what
other food assistance programs do they and household
members participate (e.g., WIC, school meals, snacks or
meals in daycare, after-school programs, Food
Distribution Program on Indian Reservations (FDPIR),
Commodity Supplemental Food Program (CSFP), food
kitchens, and food pantries), and with what frequency?
What is the relationship of program participation to
decisions regarding the source of food purchases?

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Timing of food assistance benefit receipt is asked
during Initial Household Interview and confirmed by
SNAP administrative data.
Initial Household Interview includes questions about
usual shopping behavior, modes of transport, and
travel costs.
Initial Household Interview includes questions about
program participation, shopping behavior, and food
access. Actual shopping destinations are reported in
food books.

Table A1 (continued)
Study Objective
3-d. What are the characteristics of food outlets that are
available to survey respondents? Do these characteristics
(e.g., location, type of store, and availability of nutritious
foods) vary by population group?

Data Source
The final database for the National Food Study will
include characteristics of food outlets within
proximity to each survey respondent. These
characteristics will be provided in summary form
(counts of retailers by type) after identifying
retailers within certain radii of each survey
respondent using a commercial directory of food
stores and eating places loaded in mapping
software.

4. Estimate the influence of income and prices on food purchases, including, to the extent feasible, income,
own-price, and cross-price elasticities for purchased food items (both at home and away.)
a.

b.

For the sample population as a whole, what are the
income and price elasticities of major food categories and
subcategories?
How do the estimated elasticities above vary across SNAP
participants, nonparticipating low-income households,
and higher income households?

Elasticities of demand for food can be estimated
using: household income reported in Final
Household Interview; FAH prices obtained from
receipts, Nielsen data, or imputed; FAFH prices
reported in telephone interviews, obtained from
receipts, or imputed.

5. Assess levels of food security of the population universe and subgroups using the 30-day, adult food security
measure.
a.

To what extent do levels of food security vary across
different food acquisition patterns? For instance, do
households that have lower levels of food security also
have a higher propensity to obtain foods and prepared
meals from friends or relatives?

Final Household Interview includes the food security
module. Sources of food are identified in food
books.

b.

To what extent do levels of food security relate to
measures of current food expenditures, program
participation, access to and utilization of various types of
stores, and frequency of food shopping?

c.

How do levels of food security vary among the population
groups: SNAP participants, nonparticipating low-income
households, and higher-income households?

Final Household Interview includes food security
questions. Food expenditures and shopping
frequency are derived from FAH and FAFH records.
Initial Household Interview includes program
participation. Food store access is derived from
household and retailer locations in proximity to
respondents’ homes.

d.

How do levels of food security vary between SNAP
households and eligible but nonparticipating households?

Final Interview Interview includes food security
questions. Income, resource, and expenditure
information to estimate SNAP eligibility collected by
Final Household Interview.

6. Assess levels of knowledge about diet, nutrition, and health.
a.

What do responding households know about diet,
nutrition, and health? What are the relationships between
respondents’ knowledge and the foods they purchase or
otherwise acquire? To what extent do relationships
between knowledge and food acquisition patterns vary by
population group?

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Final Household Interview includes questions about
diet, nutrition, and health knowledge.

Table A1 (continued)
7. Assess why food purchase and food security outcomes differ for SNAP participants and low-income
nonparticipants, and identify the factors that account for those differences.
a.

What are the roles of a household’s current
socioeconomic characteristics, such as current income
and current household structure?

Initial Household Interview includes questions
about household structure (household roster), and
recent changes in composition;

b.

What other dynamic factors at the household level might
affect outcomes, including the role of income volatility
and recent or unexpected household events, such as
changes in household composition and changes in
employment status?

Final Household Interview includes questions about
current household income.

What are the roles of other broad components of
household expenditures (e.g., medical expenses or
housing costs) that might be large relative to those of
other households of similar income or to the household’s
past expenditure patterns?

Final Household Interview includes questions about
non-food household expenditures.

c.

Final Household Interview includes questions about
major life events (dynamic factors).

8. Identify subject areas and groups of SNAP households for which additional information about diet, nutrition
and health could have the greatest potential impact on improved food choices.
a.

a

Identify groups of SNAP households with food acquisition
patterns and food choices that indicate possible nutrient
deficiencies.

Acquired food items will be matched with nutrient
data from USDA’s Standard Reference Database
(SR21). MyPyramid units will be merged by SR21
food codes.

Analyses by “population group” will compare SNAP participants with low-income and higher-income nonparticipants.

Table A2 prioritizes the research objectives and the data that will support the corresponding research
efforts. When the National Food Study uses multiple data sources for a single data element, the table
also ranks the sources in terms of their expected contributions for the data element. For example, for food
items acquired primarily for consumption at home (FAH), the National Food Study will rely on three
separate sources of data: respondent scanning of barcodes on food items; respondent listing of items on
the Blue Pages of their food books; and grocery receipts. These three sources are ranked as a, b, and c,
respectively, because the best source of information is scanned barcodes. The study asks respondents to
list a food item on a Blue Page of their food book only if the item’s barcode cannot be successfully
scanned. Finally, the study will use item information from the grocery receipt only if a food item was not
scanned and was not listed on a Blue Page. Grocery receipts will be used primarily to provide
information on item prices and use of store cards and manufacturers’ coupons. Receipts generally
provide only limited descriptions of the items purchased and, for this reason, are ranked last among
sources of information about what food items have been purchased and in what quantities.
The symbol “x” is used to denote some rankings in Table A2. An “x” indicates that the data sources for
the corresponding data element are ranked under a different research objective, as identified in the table.
To reiterate, he rankings in Table A2 represent the hierarchy of sources for a data element. The National
Food Study includes a great deal of complementary data collection that, at first glance, may appear to be
redundant. Alternative sources of data are used only when a higher-ranked source is not available or
when they provide other information that is not available elsewhere, as with prices on grocery receipts.

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Table A2. Data Element Priorities / Data Source Rankings
Study
Objective

Rank

Data Element / Source

Priority 1: Food item prices and quantities
1-a-i
1-a-i
1-a-i
1-a-i
1-b-i
1-b-i
1-b-i
1-b-i
1-b-i
1-b-i
1-b-i

a
b
c
a
b
c
a
b

1-b-i
1-b-i
1-a-ii

c
d

1-a-ii
1-a-ii
1-a-ii
1-b-i

a
b
c

1-b-i
1-b-i
1-b-i
1-b-i

a
b
c

1-b-i
1-b-i
1-b-i
1-i
1-i
4-a
4-a

a
b
c
x
x

Identification of food items acquired primarily for consumption at home (FAH)
Scanned barcodes
For items that cannot be scanned, listed items on Blue Pages
Receipts, when they provide detailed information
Quantities of food items acquired primarily for consumption at home (FAH)
Scanned barcodes
For items that cannot be scanned, listed items on Blue Pages
Receipts, when they provide detailed information
Prices of food items acquired primarily for consumption at home (FAH)
Receipts
If receipt is missing, Blue Pages provide total cost of purchase and whether coupons
or store card were used
Match of barcode information to retailer-specific data base
Match of barcode information to other price data base like Nielsen
Identification of prepared foods and beverages acquired primarily for consumption away
from home (FAFH)
Respondent phone calls to Survey Operations Center (SOC)
If calls not completed, review of receipt
If calls not completed, item descriptions from Red Pages
Quantities of prepared foods and beverages acquired primarily for consumption away from
home (FAFH)
Respondent phone calls to Survey Operations Center (SOC)
If calls not completed, review of receipt
If calls not completed, item descriptions from Red Pages
Prices of prepared foods and beverages acquired primarily for consumption away from
home (FAFH)
Respondent phone calls to Survey Operations Center (SOC)
If calls not completed, review of receipt
If calls not completed, item descriptions from Red Pages
Weekly food expenditures
Based on data elements described in Objective 1-b-i
Price elasticities of major food categories and subcategories
Based on data elements described in Objective 1-b-i

Priority 2: Nutritional measures; SNAP participation and eligibility; household income
1-d
1-d
1-d
1-d
1-d
1-d
1-e
1-e
1-g
1-g
1-g
1-g
1-g
1-g
1-g

a
b
a
b
a
a
b
a
b
c

Nutrient characteristics of food items acquired primarily for consumption at home (FAH)
Match of barcode/other information to food groupings in UPC data dictionary
Match of barcode/other information to USDA's Standard Reference Database (SR21)
Nutrient characteristics of prepared foods and beverages acquired primarily for
consumption away from home (FAFH)
Match of product information to food groupings in UPC data dictionary
Match of product description to USDA's Standard Reference Database (SR21)
For each household member, what purchase/acquisition occasions occur each day?
Daily Lists
Total household income
Final Household Interview
Screener
Household participation in SNAP
Match with State administrative data after survey period
Self-report during screener
SNAP list at beginning of survey

Note: Hierarchy of rankings is a, b, c, x, with x indicating that rankings are provided elsewhere in table.

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Table A2 (continued)

Study
Objective
2-b
2-b

Rank
x

2-b
2-c
2-c
3-a
3-a

x

3-a
4-a
4-a

b

x
a

x

4-b
4-b

x

Data Element / Source
Nutritional measures by population subgroups
SNAP participation and total household income based on data elements described in
Objective 1-g
Household characteristics based on data elements described in Objective 3-a
Nutritional measures among households eligible for SNAP but not participating
Based on data elements described in Objectives 1-j and 2-a
Household characteristics
Initial Household Interview for age, gender, education, race/ethnicity, disabilities,
marital status, employment
Final Household Interview for special dietary needs, health status
Income elasticities of major food categories and subcategories
Based on total household income and food item descriptions and quantities
described in Objective 1-g
Variation of income and price elasticities across SNAP participants, nonparticipating lowincome households, and higher-income households
Based on data elements described in Objective 1-g

Priority 3: Factors affecting household demand for food; eligible non-participants
1-f
1-f
1-j
1-j
1-j

a
x
a

1-j
2-a

b

2-a
2-a
2-a

a
b

2-a
2-a
3-a
3-a
3-a
3-b
3-b
3-c
3-c
3-c
5-a
5-a
5-a
5-b

a
b

5-b
5-b
5-b
5-b
5-b
5-c
5-c
5-c

a
x
x
x
x

5-d
5-d

a
b
a
a
b
a
x

a
x
x

For each household member, what meals and snacks are consumed each day?
Meals and Snacks Form
SNAP-eligible nonparticipants
Total household income based on data elements in Objective 1-g
Net household income based on expenditures on utility, medical, dependent care and
child support costs
Asset test regarding total assets and vehicle ownership
MyPyramid food group units of food items acquired primarily for consumption at home
(FAH)
Match of barcode/other information to food groupings in UPC data dictionary
Match of barcode/other information to USDA's Standard Reference Database (SR21)
MyPyramid food group units of food items acquired primarily for consumption away from
home (FAFH)
Match of product information to food groupings in UPC data dictionary
Match of product description to USDA's Standard Reference Database (SR21)
Where respondents shop
Daily Lists, Blue Pages, Red Pages for shopping during data collection week
Initial Household Interview for "usual" shopping destinations
Travel times and cost
Initial Household Interview
Participation in food assistance programs other than SNAP
Initial Household Interview
Blue Pages indicate when WIC purchases are made
Household food security-variation by food acquisition patterns
Final Household Interview includes food security questions
Sources of food based on data elements described in Objective 3-a
Household food security-variation by food expenditures, program participation, access to
stores, and food shopping frequency
Final Household Interview includes food security questions
Food expenditures based on data elements described in Objective 1-b-i
Program participation based on data elements described in Objectives 1-g and 3-c
Store access based on data elements described in Objective 3-d
Food shopping frequency based on data elements described in Objective 1-e
Household food security-variation by SNAP participation and total household income
Final Household Interview includes food security questions
SNAP participation and total household income based on data elements described in
Objective 1-g
Food security among households eligible for SNAP but not participating
Based on data elements described in Objectives 1-j and 2-a

Note: Hierarchy of rankings is a, b, c, x, with x indicating that rankings are provided elsewhere in table.

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Table A2 (continued)

Study
Objective
7-a

Rank

7-a

x

7-b
7-b

a

7-c
7-c
8-a

a

8-a

x

8-a

x

Data Element / Source
Factors that account for differences in food purchases and food security-household
socioeconomic characteristics
Household socioeconomic characteristics based on data elements described in
Objectives 1-g and 3-a
Dynamic factors that account for differences in food purchases and food security
Final Household Interview includes questions about major life events (dynamic
factors)
Other major expenditures that account for differences in food purchases and food security
Final Household Interview includes questions about major expenditure categories
Characteristics of SNAP households with food acquisition patterns that indicate possible
nutrient deficiencies
Characteristics of SNAP households based on data elements described in Objectives
1-g and 3-a
Nutrient characteristics based on data elements described in Objectives 1-d and 2-a

Priority 4: Timing of acquisitions; diet, nutrition, and health
1-h
1-h
1-h
1-h
1-h
1-h
3-d
3-d
3-d
6-a
6-a

a
b
a
b
a
b
a

6-a
6-a

x

6-a
6-a

x

Timing of food acquisitions
Receipts
If receipt not available, use day/date information from Daily Lists, Blue Pages, Red
Pages
Timing of food acquisitions relative to paydays and benefit issuance days
Initial Household Interview
Match with State administrative data after survey period
Characteristics of food outlets
Match of survey record to STARS database of SNAP-authorized retailers
Match of survey record to commercial directory of food stores and eating places
Knowledge about diet, nutrition and health
Final Household Interview includes questions about knowledge about diet, nutrition
and health
Knowledge about diet, nutrition and health-variation by foods acquired
Acquired foods based on data elements described in Objectives 1-a-i, 1-a-ii, 1-b-I, and
1-b-ii
Knowledge about diet, nutrition and health-variation by population group
Population groups based on data elements described in Objectives 1-g, 3-a, and 3-c

Note: Hierarchy of rankings is a, b, c, x, with x indicating that rankings are provided elsewhere in table.

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