Using Paradata to Evaluate Youth Participation in a Digital Diary Study.

We analyze recruitment, access and longitudinal response paradata from a year-long intensive longitudinal study (mDiary) that used a mobile-optimized web app to administer 25 bi-weekly diaries to youth recruited from a birth cohort study. Analyses investigate which aspects of teen recruitment experiences are associated with enrollment and longitudinal response patterns; whether compliance behavior of teens who require multiple invitations to enroll differs from that of teens who enroll on the first invitation; and what personal and social circumstances are associated with different longitudinal compliance patterns. Latent Class Analysis (LCA) is used to derive longitudinal compliance classes. mDiary's person-survey response rate of 70 percent is noteworthy considering reports that response rates for smartphone studies trail those administered via telephone or personal computers. Conditional on agreeing to participate, teens with texting capability were over six times as likely to enroll as their peers lacking access, and they also completed 6-7 more diaries. Youth who required multiple prods to register not only were less likely to enroll than their peers who registered at the first invitation, but also tended to attrite early. Compared with teens who completed all 25 surveys, those who attrited early had less access to texting capability, home Internet service, and had low-education mothers. Consistent with studies of adults, nonparticipants were disproportionately black males from socioeconomically disadvantaged backgrounds.