Optimizing follow-up and study retention in the 21st century: Advances from the front line in alcohol and tobacco research.

AIMS: Longitudinal studies are integral in addiction research but retention of participants over time can be challenging. While statistical algorithms for missing data have advanced, they remain less desirable than collecting actual data with high retention rates. An update to methodological primers with consideration of evolving technology and privacy concerns is needed for 21st century researchers.
METHODS: Comprehensive follow-up methodological strategies were conducted in four concurrent laboratory- and intervention-based studies across N=697 drinker and smokers enrolled in studies at the Clinical Addictions Research Laboratory at the University of Chicago. The methods of three key longitudinal research themes and their outcomes are outlined, including: a) mindset of the research team starting at study enrollment, b) modalities with a particular focus on advances in technological strategies in follow-up, and c) mitigating difficult to reach and challenging participants.
RESULTS: The techniques described herein produced follow-up rates of 95% and 99% in two laboratory-based studies with follow-ups of 1- and 6-years, respectively and 94% and 97% in two intervention studies with follow-ups of 6- and 12- months. Adapting incentive strategies more than tripled on-time follow-up, from 18% to 68% of the sample, switching to more advanced technologies decreased participant burden and time by 30% from traditional telephone interviews, and difficult-to-reach participants averaged 47 contact attempts.
CONCLUSIONS: The methods presented produced exceptional follow-up retention across four studies. The principles and methodologies discussed may be modified across a range of studies to target various sub-populations in the addiction field.