Table 3.
Statistical Power Estimates
| Method | N | WA β1 | Avg. Est. β1 | St. Bias β1 | Coverage β1 | C β1 Power | D β1 Power | E β1 Power | WA β1 Power |
|---|---|---|---|---|---|---|---|---|---|
| LCPMM | 150 | -.214 | -.2312 | .1071 | .920 | .113 | .169 | .113 | .382 |
| 250 | -.214 | -.2266 | .1057 | .937 | .336 | .076 | .346 | .539 | |
| 353 | -.214 | -.2337 | .1916 | .926 | .460 | .085 | .093 | .678 | |
| 450 | -.214 | -.2296 | .1710 | .926 | .546 | .093 | .100 | .755 | |
| LGM | 150 | -.214 | -.2311 | .1196 | .943 | - | - | - | .411 |
| 250 | -.214 | -.2270 | .1124 | .925 | - | - | - | .589 | |
| 353 | -.214 | -.2352 | .2158 | .916 | - | - | - | .737 | |
| 450 | -.214 | -.2307 | .2026 | .919 | - | - | - | .799 |
Notes: LCPMM = Latent Class Pattern Mixture Model. LGM = Latent Growth Model. WA β1 = Weighted-averaged treatment effect on the in-treatment slope. C β1 = Completers treatment effect on the in-treatment slope (60% of the population). D β1 = Dropouts treatment effect on the in-treatment slope (20% of the population). E β1 = Erratics treatment effect on the in-treatment slope (20% of the population). Avg. Est. = Average Estimate across 1000 replications. St. Bias = Standardized Bias (values above .40 indicate problematic bias; Collins et al., 2001). Coverage = values below .90 indicate problematic coverage rates.