Formative research implications on design of a randomized controlled trial for oral health promotion in children.

We conducted this comprehensive formative assessment to determine the feasibility and acceptability of the CO-OP Chicago trial. While overall acceptance of the trial was high, the results highlighted specific issues with the proposed trial implementation plan and led to several critical design changes. This type of formative work requires a significant upfront investment but we expect it will translate into savings through better recruitment, retention, intervention implementation and adherence, and result dissemination.