2019 Food Safety and Nutrition Survey (FSANS)
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Methodology
The respondents for this survey were English- or Spanish-speaking noninstitutionalized adults
(≥18 years old) living in the 50 U.S. states and the District of Columbia. Address-based sampling
was used to draw a nationally representative sample of households. Respondents within the
household were randomly selected using the Hagen-Collier within-household sampling scheme
to randomly identify one adult.
Each selected household received up to five mailings requesting participation in the study. The
first was a notification letter on FDA letterhead introducing the study and providing the
information necessary (the URL [i.e., website address] and a unique personal identification
number [PIN] assigned to each selected household) to complete the study by visiting an FDA
website. That first mailing contained two $1 bills to encourage response and maintain data
quality. The second mailing, a thank you/reminder postcard, was sent three days after the initial
letter, and was followed six days later by the third mailing, which was a second reminder letter.
The fourth mailing, sent 20 days after the initial mailing to those who had not yet responded,
contained a letter, a survey booklet, and a pre-paid return envelope for respondents to use. Four
days after the fourth mailing, researchers sent the fifth and final contact, a mail survey reminder
postcard that also included instructions on how to access the web version of the survey.
Addresses in zip codes with high density Hispanic populations according to the US Census (20%
Hispanic or higher) received two-sided letters in Contacts 1, 3, and 4 with information in English
and Spanish.
The FDA survey webpage provided commonly asked questions about the study in both English
and Spanish, and a link that routed each participant to the survey host website. Once on the host
website, the respondents entered their assigned PIN to begin the survey. Each respondent was
randomly assigned to one of the two versions of the survey: Food Safety or Nutrition. Some
overlapping questions were asked on both versions.
Survey data were weighted to account for sampling design and non-response. Because all of the
US addresses had the same chance of being selected, the base weights are the same for all the
sampled addresses. Base weights were adjusted with data from the sample frame (Census region,
single or multi-unit housing); the number of adults per household; and demographic controls
from the latest release of the 5-year American Community Survey data (2014-2018 ACS data)
for sex, age, race, Hispanic origin, education, Census region, and residence in a metropolitan
area.