Background
Retention of study participants in randomized controlled trials (RCTs) is crucial to study validity.
Purpose
We analyzed the result of four retention strategies used to reconnect with urban teens enrolled in a school-based randomized controlled trial (RCT) and overdue for a 12-month follow-up survey.
Methods
Traditional retention strategies used to reconnect with teens categorized as “unable to contact” were weekly re-dials of non-working telephone numbers and mailings to the student’s home. Non-traditional retention strategies were obtaining assistance from school administration and communication through Facebook.
Results
Of the 422 students enrolled, 125 (29.5%) were overdue for a 12-month follow-up survey, but had no working telephone number (unable to contact). We made 196 attempts to contact these 125 students, of which 82 attempts (41.8%) were successful in “reconnecting,” defined as (1) a student contacting research staff as a result of a mailed notice; (2) a research staff member leaving a voicemail at a previously disconnected telephone number; (3) a student responding to Facebook outreach; or (4) research staff obtaining a new telephone number and talking to a person at the new telephone number. We used “ mailed reminder letters” as the referent category, in our analysis. Odds ratios (95% confidence intervals) for the association between the strategy used and success (“reconnecting”) for telephone number re-dials, Facebook, and school administration assistance were 4.60 (1.8–11.8), 1.94 (1.01–3.73), and 2.91 (0.58–14.50), respectively.
Limitations
Retention strategies were not applied hierarchically or systematically across students, and we were unable to ascertain student preference for a particular strategy. In addition, our findings may be applicable only to study populations with characteristics similar to those of students included in this study.
Conclusion
Overall, of the 422 students who enrolled in the study, 380 (90%), ultimately completed the 12-month follow-up survey. A mix of traditional retention strategies, such as telephone number re-dials, and more contemporary methods, such as use of Facebook, were effective in reconnecting with urban teenagers enrolled in a school-based RCT, and controlling attrition during the 12-month follow-up survey period.