The effect of home visits as an additional recruitment step on the composition of the final sample: a cross-sectional analysis in two study centers of the German National Cohort (NAKO)

Abstract

Background Participation in epidemiologic studies has been declining over the last decades. In addition to postal invitations and phone calls, home visits can be conducted to increase participation. The aim of this study was therefore to evaluate the effects of home visits in terms of response increase and composition of the additionally recruited and final sample. Methods In the framework of the German National Cohort (NAKO) recruitment process, two of 18 study centers, Halle (Saale) and Berlin-Center, performed home visits as additional recruitment step after postal invitation and reminders. Response increase was calculated and differences between participants recruited via home visits and standard recruitment were examined. Proportions are presented as percentages with 95%-confidence intervals. Results In the general population in Halle, 21.3-22.8% participated after postal invitation and two reminders in the five assessed recruitment waves. The increase of the overall response was 2.8 percentage points (95%confidence interval: 1.9-4.0) for home visits compared to 2.4 percentage points (95%CI: 1.7-3.3) for alternatively sent third postal reminder. Participants recruited via home visits had similar characteristics to those recruited via standard recruitment. Among persons of Turkish descent in Berlin-Center site of the NAKO, home visits conducted by native speakers increased the participation of women, persons living together with their partner, were born in Turkey, had lower German language skills, lower-income, lower education, were more often smokers and reported more often diabetes and depression to a degree which changed overall estimates for this subsample. Conclusions As an additional recruitment measure in the general population, home visits increased response only marginally, and the through home visits recruited participants did not differ from those already recruited. Among persons with migration background, home visits by a native speaker increased participation of persons not reached by the standard recruitment, but the effects of using a native speaker approach could not be separated from the effect of home visits.

Anxiety, depressive symptoms, and distress over the course of the war in Ukraine in three federal states in Germany

“…In an additional effort, potential respondents were even visited at home. In a previous analysis, we demonstrated that those recruited with the extensive efforts of home visits did not differ from those recruited before ( 36 ). In the DigiHero study, only a single invitation was sent, accepting a lower response at higher efficiency.…”

To Remind or Not to Remind During Recruitment? An Analysis of an Online Panel in Germany

“…In addition to considerations related to single assessments, there is also a longitudinal perspective. Although further efforts during recruitment (e.g., through reminder letters, phone calls, and home visits) result in an increase in response proportions [5,6,19,20], studies have indicated that participants recruited with more effort drop out earlier and are therefore of limited benefit for longitudinal studies [10,18]. These participants may be different from those who remain in the study, but if they are lost, there is not much that can be done to control for this selection.…”