Number of pages completed
REGRESSION
The average number of pages completed per diary returned varied from 7 to 36 pages across both intervention groups. Median and IQR average pages completed by the intervention group at the site level were 35 (34, 35) pages and 35 (35, 35) pages for the non-conditional and conditional incentive groups, respectively. Corresponding values for the subset (9 pairs) where both constituent sites had at least one diary returned were 35 (34, 35) pages and 35 (35, 35) pages for the non-conditional and conditional incentive groups, respectively. When returned, the diary was generally fully completed or almost fully complete; only 7 (3%) across all participants failed to return at least 30 pages when the diary was returned. By intervention group, this was 4 (3%) and 3 (3%), respectively, for the non-conditional and conditional intervention groups.Regression analysis adjusted for cluster pair was a mean difference between interventions of 0.5, 95% CI (− 1.2, 2.3) pages, 