Sample size: planned number of clusters
Part 1: The total population-representative sample included 112,861 individuals, of which info = 2,559, info&form = 7,700, and control group = 102,602. Treatment was not clustered (randomization at individual level)
Part 2: The total number of new residents in the sample were 6,906 individuals, of which 3,454 treated and 3,452 controls. Randomization clustered by residential address (6,059 clusters).
The estimation samples in our planned analyses will deviate from the above for three reasons:
1. (Non-selective) Attrition. For the sample in Part 1, 137 individuals died or left the region before we extracted address information (for administrative reasons, address data was extracted after the randomization date) and an additional 146 individuals were de-registered from the region before the leaflets were mailed out in the last week of February. One individual chose to opt out from the study after randomization. For the sample in Part 2, we lack data for one individual for administrative reasons and 102 individuals died or left the region between randomization and intervention.
2. The analyses will exclude individuals who, at baseline, were registered at a PCC in a rural area.
3. The analyses of new residents will exclude recent immigrants.
With these restrictions, the size of the Part 1 sample equals 69,744 (info = 1,578, info&form = 4,751, control =63,415) and the Part 2 sample equals 3,157 (1,597 treated) individuals and 2,843 (1,418 treated) clusters
See analysis plan for more information.