Table 2.
Fit Indices for 1- to 4-Class Unconditional Growth Mixture Models of PTSD Symptoms
| Growth mixture model |
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|---|---|---|---|---|---|---|---|---|
| Linear weights only |
Linear + quadratic weights |
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| Fit indices | 1 Class | 2 Class | 3 Class | 4 Class | 1 Class | 2 Class | 3 Class | 4 Class |
| AIC | 4304.46 | 4182.91 | 4130.07 | 4066.68 | 4257.46 | 4187.66 | 4116.73 | 4066.68 |
| BIC | 4329.92 | 4205.18 | 4174.61 | 4141.51 | 4292.46 | 4222.67 | 4177.01 | 4139.89 |
| SSBIC | 4304.58 | 4183.01 | 4130.28 | 4087.67 | 4257.62 | 4187.82 | 4117.01 | 4067.02 |
| Entropy | – | .97 | .97 | .96 | – | .96 | .98 | .99 |
| LRT | – | p = .07 | p = .46 | p = .16 | – | p = .49 | p = .14 | p = .18 |
| BLRT | – | p < .001 | p < .001 | p < .001 | – | p < .001 | p < .001 | p = .15 |
Note: N = 178. PTSD = Posttraumatic stress disorder; AIC = Akaike information criterion; BIC= Bayesian information criterion; SSBIC = sample size adjusted Bayesian information criterion; LRT = Lo-Mendell-Rubin test; BLRT = bootstrap likelihood ratio test.