The use of online methods to recruit and follow a hard-to-reach population in the Peer Alternatives for Addiction Study 2021 Cohort.

Study methods appear to have produced a valid, largely representative sample of the hard-to-reach target population that was successfully followed across 12 months. However, given the high survey elimination rate and need for extensive data review, we recommend that researchers avoid open-link designs and include comprehensive data review when incorporating online design elements.