The Effects of Alternative Mixed-Mode Household Screening Protocols and Invitation Letter Envelope Types on Participant Recruitment: Evidence from the Health and Retirement Study

With declining survey response rates, researchers have been exploring effective strategies for participant recruitment. This study considered the household screening stage of recruitment in the 2022 Health and Retirement Study (HRS), a national panel study. The study investigates the effects of different contact protocols and invitation letter envelope types on completion outcomes and contact attempts, specifically focusing on the variation in effects among race/ethnicity and HRS cohorts. A total of 16,452 sampled households were divided randomly into two groups. One received a web-field protocol, where sampled individuals were invited to complete the questionnaire online and nonrespondents were eventually followed up FTF (face-to-face), and the other received a field-only (FTF) protocol. Within the former group, two random subgroups were created. One group received a standard HRS mailing envelope containing the invitation letter and a prepaid $2 bill cash incentive. The other received a visible cash envelope with a window showing the incentive. Logistic regression models were employed to analyze completion outcomes by screening protocol and envelope type. Interaction terms were subsequently included to explore differences in these effects among race/ethnicity and HRS cohorts. Linear regression and Poisson models were used to assess predictors of the number of contact attempts needed among completed cases. Findings show that the web-field protocol improved completion rates and reduced contact attempts among the youngest cohort, but had a negative effect among Hispanic households. The type of envelope also significantly influenced screener completion. Receiving a standard envelope increased response likelihood among non-Hispanic Black households. The youngest cohort also exhibited a higher likelihood of response with a standard envelope and generally received fewer contact attempts with both types before completion. However, visible cash did not present strong effectiveness. Overall, the findings highlight the effectiveness of employing different contact methods to enhance survey participation, specifically among different socio-demographic subgroups.