Time to diary return
REGRESSION
The individual time to return ranged from 10 to 64 days across both intervention groups. Median and IQR of the average times to return by intervention group at site level were 23 (20, 26) days and 21 (19, 25) days 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 24 (23, 25) days and 21 (19, 24) days for the non-conditional and conditional incentive groups, respectively.Regression analysis adjusted for site pair was a mean difference between interventions of − 0.9, 95% CI (− 5.7, 3.8) days, 