Table 2 Calculation of decay in prevention effects by age 25
From: School-based smoking prevention programs with the promise of long-term effects
Average school-only RI = | 30.00% |
Average school + community/media RI = | 40.00% |
Without the prevention | Â |
Average proportion not smoking in high school who will start by age 25 (SAMHSA Household Survey 1989–99) | 3.12% |
Average high-school daily smoking without intervention (Monitoring the Future, 2003) | 15.80% |
Proportion of new smokers by age 25 = | 2.63% |
Therefore, total proportion smoking by age 25 = | 18.43% |
With school-based prevention | Â |
Proportion smoking after school-based prevention = | 11.06% |
Therefore, proportion not smoking = | 88.94% |
Therefore, proportion new smokers by 25 = | 2.77% |
Therefore, total proportion smoking by age 25 = | 13.83% |
Therefore, new RI = | 24.9% |
Decay in RI = | 16.9% |
With school + community/media prevention | Â |
Proportion smoking after school-based prevention = | 9.48% |
Therefore, proportion not smoking = | 90.52% |
Therefore, proportion new smokers by 25 = | 2.82% |
Therefore, total proportion smoking by age 25 = | 12.30% |
Therefore, new RI = | 33.2% |
Decay in RI = | 16.9% |