Data collection and measurement
SECONDARY
We did a repeat survey after six months using the same tools and approach described in detail in the baseline study [Self-reported lifejacket wear was measured as a binary variable: boaters who “always wore a lifejacket while on the lake” were considered to have self-reported lifejacket wear, and were assigned to “yes” category and the rest to “no” category. The secondary outcome was self-reported lifejacket ownership which was assessed through interviews with the boaters. Because the sampling was random, the boater who were observed were not necessarily same who were interviewed for self-reported wear. Four Research Assistants (RAs) were trained about all aspects of data collection, objectives, protocol, and standard operating procedures. The RAs were provided with a pictorial manual of the different types of lifejackets and boats for reference while in the field. They had a minimum of bachelor’s degree, and were native speakers of the languages most spoken in the study area. Single blinding was done to maintain internal validity and reduce exposure identification and interviewer bias by using RAs who did not know which clusters were in the non-intervention or intervention arm.