Results

Reasons for Refusal and Concerns at Introduction Stage

The percentage of all Sample Adults who gave a reason for refusing among those who mentioned a concern are shown in Table 4. Of the 806 Sample Adults who refused to be contacted for FHS when asked by the FR, 80.5% (n = 649) responded to the question, “Please tell me the main reason why you don’t want to take part in this study.” The nine categories identified in the Sample Adult verbatim refusal reason coding (Appendix XVII) were: lack of interest, lack of time, privacy concerns, don’t want someone in the home, study collects too much information, government distrust, other family members had concerns, and the respondent had family obligations, a needle or blood phobia, or some other reason. The most common reasons mentioned were lack of interest (44.7%), lack of time (26.0%), and privacy concerns (16.5%).

Table 4

Reasons given by Sample Adults for refusing and agreeing permission to pass contact information to National Health Interview Survey Follow-up Health Study staff

The lack of interest category included subcategories such as “My doctor will do or did those tests,” “I already get enough tests,” and “I’m healthy and don’t need these tests.” The lack of time category included “Too much trouble,” “Not home,” and “Inconvenient or difficult to schedule.” Privacy concerns included a mention that the study was too intrusive. However, most respondents who gave each of these three reasons did not provide any further details about their reason. Fewer Sample Adults gave a reason in any of the other six categories: 5.2% said they didn’t want someone in their home; 6.5% said the study collects too much information; 3.2% said they distrust the government; 2.2% mentioned a needle or blood phobia; and 1.5% mentioned family member concerns or obligations.

Many of these results were reported in the FR focus groups that were conducted with FRs with NHIS FHS cases, in which they discussed their experience working on the study. Sample Adult privacy concerns about NHIS FHS mentioned in the July 2021 focus group included concerns about a stranger in their home and related-COVID-19 concerns, and mistrust that the government would responsibly handle their blood and urine. Some Sample Adults did not believe that the government would not test their blood for DNA or that the government could protect their results from foreign hackers.

FRs in the October focus groups reported that Sample Adults felt that having their physical measurements and biospecimens collected was physically and personally invasive, and they were suspicious to share this additional information after already answering the long NHIS survey instrument (7). FRs in both focus groups reported that some Sample Adults said they would be willing to participate if they could go to a laboratory instead of having someone come to their home, to reduce the invasiveness, while others offered their results from a recent physical examination, to reduce burden (7).

Sample Adult time concerns mentioned in the July 2021 FR focus group included a reluctance to spend an additional hour on the home visit after already spending an hour on the interview, and concern that the home visit would take longer than an hour. Also, although they may result from different causes, FRs reported that time concerns were common across socioeconomic groups. For example, one FR reported, “Time is valued by people for different reasons—affluent people say $75 isn’t enough money, [while] people working from dawn ‘til dark really value their weekends.”

Reasons for Agreement at Introduction Stage

As described in the Methods section, if the Sample Adult agreed, the instrument asked the FR to provide the Sample Adult’s reason for agreeing. If the Sample Adult did not give one, the FR could enter that information as well or leave the field blank. Of the 354 Sample Adults who agreed to be contacted for NHIS FHS when asked by the FR, 47.2% (n = 167) gave a reason for participating (Table 4). The seven categories identified via the reasons for agreeing coding were: monetary incentive, interest in or expectation of enjoying the study, free examination or test results, belief that the study is important, helping people or contributing to the public good, no reason not to, and other.

Of those who gave a reason, 7.2% (n = 12) gave more than one reason. Among the 167 participants who provided a reason for agreeing to be recorded by the FR, the most common answers were the monetary incentive (18.6%), interest in or expectation of enjoying the study (18.6%), and free examination or test results (16.8%) (Table 4). The next three most commonly mentioned reasons were belief that the study is important (14.4%), a desire to help people or serve the public good (13.8%), and didn’t see any reason not to because it was not inconvenient (10.2%). Among the 15% of Sample Adults who reported other reasons for participating, six mentioned their healthcare background, five agreed after learning there was scheduling flexibility, three Sample Adults agreed because it supported their identity (for example, as a nice person), three agreed because a family member gave them permission to participate, two agreed after learning they could skip parts, and six gave other reasons.

Reasons for Refusal During Scheduling

As described in the Methods section, if the Sample Adult refused, the schedulers recorded their reason, if provided. As shown in Table 3, 25 Sample Adults gave permission to be contacted but refused when contacted by a scheduler. This refusal could have been either a refusal to schedule an appointment or a refusal to reschedule an appointment. Results are presented as counts, rather than percentages, because the total number of refusals at the scheduling stage of the protocol was small. Of the 25 participants who refused during the scheduling stage, 9 indicated that they were not interested; 7 indicated that they were too busy; 3 were reluctant to provide biological samples; 1 reported that they were reluctant to allow a health representative into their home due to risk of COVID-19 exposure; 3 reported health issues of their own or of a close family member; 3 reported being uncomfortable allowing a stranger in their house; and 1 needed to travel due to a recent death in the family. (Note that 2 participants each provided 2 reasons, resulting in a total of 27 reasons given for refusal.) Eight of the 25 cases scheduled an appointment that did not occur and subsequently refused during an attempt to reschedule. In two cases it was not possible to identify a location for the home examination acceptable to both the Sample Adult and the health representative (as noted previously, while inside the participant’s home was the recommended location, the participant could request a different location, such as their porch or workplace), one Sample Adult did not provide a reason, one Sample Adult said they thought it was a scam and also had “too much going on,” one Sample Adult lost interest after learning more about what the visit included, one mentioned an arthritis flare-up, one did not have time, and one would be traveling.

Participant Concerns Assessed in Post-examination Survey

About 23% (22.7%, n = 40) of study participants who completed an examination reported in the post-examination survey that they had concerns. The nine categories of reasons coded by Westat staff were privacy or confidentiality, legitimacy of the study, specimen collection, making time for the home visit, stranger in the home or personal safety, unclear about what visit includes, cleaning home before the visit, dogs in home, and other. Concerns only mentioned by one participant were grouped into the other category.

As shown in Table 5, privacy issues and the confidentiality of their information was mentioned by about one-quarter of participants (27.5%), followed by the legitimacy of the study and specimen collection (15.0% each). Concerns surrounding specimen collection included that they would faint during the blood draw, reluctance to have the tests for liver and kidney function, and the success of the blood collection because the participant could be a difficult draw. Fewer participants reported concerns about making time in their schedule, safety concerns associated with allowing a stranger in their home, confusion about what the visit included, concerns about having to clean their home before the visit, and dogs in the home. Concerns mentioned by a single participant were categorized as “Other” and included the participant forgetting about the scheduled appointment, ensuring that the health representative had been vaccinated against COVID-19, and the participant’s low blood pressure.

Table 5

Percentage of National Health Interview Survey Follow-up Health Study examination participants who reported concerns about participating, by type of concern

Participant Motivation Assessed in Post-examination Survey

At the end of the examination, participants were asked, as shown in Appendix XIV, “Please tell me yes or no, whether you took part in this study for any of the following reasons: free test results, the $75 prepaid card, help with health efforts in the United States, improve information used by policymakers, some other reason.”

The top panel of Table 6 shows the percentage of participants who completed an examination (n = 176) who answered “yes” to each of these reasons for participating. To help with health efforts in the United States was the reason most frequently indicated (88.6%), followed by improving information used by policymakers (72.7%). Slightly less than 60% each said that the free test results (58.0%) and the $75 prepaid card (58.5%) motivated their participation.

Table 6

Participant reasons for participating in National Health Interview Survey Follow-up Health Study examination

Of the 30 participants (17.0%) who provided some other reason, 6 provided reasons related to monitoring their health, and 6 expressed a desire to support research studies because they worked in research or a science-related field, had personally benefited from research studies, or liked participating in research. Civic duty and wanting to help others were mentioned by four participants each. Three participants said it sounded interesting, it gave them something to do, or they were curious about the study. Three participants agreed because they were asked or because the U.S. Census Bureau field representative was nice. The remaining four participants offered responses ranging from “Curious why I was asked,” “Chose me because of my nationality,” “Haven’t done it in so long,” and “None.”

After being asked about each possible reason individually, participants were then asked to identify their main reason for participating. Specifically, they were asked, “What was your main reason for taking part in this follow-up study?” The distribution of the main reason for participating is shown in the bottom panel of Table 6. About 40% of participants reported that helping with health efforts was the main reason. Free test results and the prepaid card were each listed as the main motivator by one-fifth of participants. Improving information used by policymakers was the main reason for 8.0%, 6.3% said some other reason, and 9.1% did not provide a main reason.