Table 3.
Comparison of model fit statistics
| Model fit indices | Model 1a | Model 2b | Model 3c |
|---|---|---|---|
| Akaike’s information criterion (AIC) | 725.6 | 727.0 | 799.7 |
| −2 log-likelihood-ratio statistic | 709.6 | 713.0 | 789.7 |
| Difference of −2 log-likelihood-ratio compared to Model 1 | – | 3.4 | 80.1 |
| Degree of freedom | – | 1 | 3 |
| P-value | – | P > 0.05 | P < 0.001 |
a
Includes 3 dummy variables for gap, gender, marital status, having ever injected drugs, and number of sexual partners in the past year
b
Includes all variables in Model 1 except number of sexual partners in the past year
c
Includes all variables in Model 1 except 3 dummy variables for gap