Nonresponse and Underreporting Errors Increase over the Data Collection Week Based on Paradata from the National Household Food Acquisition and Purchase Survey.

Background: Food acquisition diary surveys are important for studying food expenditures, factors affecting food acquisition decisions, and relations between these decisions with selected measures of health (e.g., body mass index, self-reported health). However, to our knowledge, no studies have evaluated the errors associated with these diary surveys, which can bias survey estimates and research findings. The use of paradata, which has been largely ignored in previous literature on diary surveys, could be useful for studying errors in these surveys.Objective: We used paradata to assess survey errors in the National Household Food Acquisition and Purchase Survey (FoodAPS).Methods: To evaluate the patterns of nonresponse over the diary period, we fit a multinomial logistic regression model to data from this 1-wk diary survey. We also assessed factors influencing respondents' probability of reporting food acquisition events during the diary process by using logistic regression models. Finally, with the use of an ordinal regression model, we studied factors influencing respondents' perceived ease of participation in the survey.Results: As the diary period progressed, nonresponse increased, especially for those starting the survey on Friday (where the odds of a refusal increased by 12% with each fielding day). The odds of reporting food acquisition events also decreased by 6% with each additional fielding day. Similarly, the odds of reporting ≥1 food-away-from-home event (i.e., meals, snacks, and drinks obtained outside the home) decreased significantly over the fielding period. Male respondents, larger households, households that eat together less often, and households with frequent guests reported a significantly more difficult time getting household members to participate, as did non-English-speaking households and households currently experiencing difficult financial conditions.Conclusions: Nonresponse and underreporting of food acquisition events tended to increase in the FoodAPS as data collection proceeded. This analysis of paradata available in the FoodAPS revealed these errors and suggests methodologic improvements for future food acquisition surveys.

Collecting Objective Measures of Visual and Auditory Function in a National in-Home Survey of Older Adults.

Maintenance of visual and auditory function is important for preventing the onset of activity limitations and preserving quality of life in later life. To date, national panel studies focused on health and aging have mostly collected subjective (self-reported) measures of visual and auditory function. The National Health and Aging Trends Study (NHATS), a study of Medicare beneficiaries ages sixty-five and older, recently developed a protocol for measuring objective visual and auditory function for its annual, in-home data collection conducted by trained interviewers. The protocol includes three vision tests-distance and near acuity and contrast sensitivity-and one hearing test-pure-tone audiometry-conducted using a tablet platform with results recorded in a scannable booklet. To identify operational issues and evaluate data quality for the proposed set of vision and hearing tests, NHATS incorporated a pilot study into its 2019 round (N = 417 participants and N = 9 interviewers). Using these pilot study data, the objectives of this paper are to: (1) describe the NHATS protocols to collect objective measures of visual and auditory function; (2) evaluate the quality of the data collected; and (3) assess whether results are influenced by interviewers. We found that respondents were highly likely to participate, with cooperation rates for each test about 90 percent. Data were high quality, with low rates of missingness, test results significantly associated with age and self-reported items, and percentages with poor vision or hearing consistent with prior population-based studies. Objective measures were more likely than self-reports to classify participants as having visual and auditory impairments and had stronger relationships with demographic correlates. Interviewer effects were small and not statistically significant in this small sample. Results of this study have demonstrated that objective visual and auditory functioning can be successfully incorporated into an interviewer-administered home-based protocol.