| Targeted enrollment; (% recruited northern, central) | Actual enrollment (northern, central) | Full data completion (northern, central) | Only partial data completion (northern, central) | Only minimal data completion (northern, central) |
---|---|---|---|---|---|
Tier I: year 1 only | Â | Â | 5 survey elements | 3-4 survey elements | 1-2 survey elements |
 | n = 750 | n = 655 | n = 580 | n = 31 | n = 39 |
 | (26%,32%) | (499, 156) | (87%,95%) | (6%,2%) | (7%,3%) |
Tier I: longitudinal (years 1-3) |  |  | 3 years | 2 years | ≤1 year |
 | See above | See above | n = 252 | n = 182 | n = 221 |
 |  |  | (38%,41%) | (25%,37%) | (37%,22%) |
Tier II: 15/18 monthsa | Â | Â | 15-18 monthly surveys | 10-14 monthly surveys | 1-9 monthly surveys |
 | n = 250 | n = 250 | 95b | 26 | 129 |
 | (77%,75%) | (186, 64) | (29%,63%) | (11%,9%) | (60%,28%) |
Tier III: 8 visits over 4 seasonsb | Â | Â | 4 collection periodsc | 2-3 collection periods | 1 collection period |
 | n = 40 | n = 47 | n = 40 | n = 4 | n = 3 |
 | (34%,52%) | (30, 17) | (90%,76%) | (7%,12%) | (3%,12%) |