Age (year) Sigma1 1 Sigma 2 Sigma 3 Sigma 4 Sigma 5 Sigma 6 Sigma 7 PDES method and the cross-sectional 1997 NSDUH dataa 13 0.880 0.070 0.050 0.193 0.807 0.476 0.526 14 0.859 0.074 0.068 0.174 0.826 0.437 0.563 15 0.836 0.089 0.076 0.187 0.814 0.400 0.600 16 0.863 0.066 0.071 0.196 0.804 0.430 0.570 17 0.891 0.045 0.046 0.148 0.853 0.442 0.558 Directly estimated with the 1997 National Longitudinal Survey datab 13 0.885 0.067 0.048 0.159 0.841 0.425 0.575 14 0.889 0.059 0.052 0.115 0.885 0.409 0.591 15 0.889 0.065 0.046 0.068 0.932 0.387 0.613 16 0.873 0.083 0.044 0.088 0.912 0.426 0.574 17 0.884 0.073 0.043 0.080 0.920 0.423 0.577 Differences between the two estimations (13-17 years old) Mean 0.002 0.020 0.076 0.076 0.020 0.020 0.016 SD 0.023 0.012 0.038 0.038 0.016 0.016 0.024 P (t test) >0.05 >0.05 >0.05 >0.05 >0.05 >0.05 >0.05 Note: aTransitional probabilities were estimated with one-year cross-sectional data from the 1997 National Survey on Drug Use and Health. bTransitional probabilities were estimated with data collected among youth who participated the baseline and the follow-up survey from the National Longitudinal Survey of Youth 1997. See Figure 1 and the corresponding text for definitions of the seven transitional probabilities. *:This sample contained only participants who provided completed data at both baseline survey in 1997 and follow-up survey in 1998.

Table 2: Transitional Probabilities Estimated with PDES Method/1997 NSDUH data (N=8,731) and the Conventional Method and the NLSY97 Data (n=7,286*).