Covariate Search Shotgun run mode
The Cov. Shotgun (shotgun covariate search) run mode option is only available for Population models. Covariates and covariate effects must be specified. This run mode performs a shotgun search to evaluate all the possible scenarios and selects the best one out of 2^(number of effects). Each effect added has the effect of doubling the number of scenarios. It creates a list of evaluated scenarios in the Scenarios Tab.
Use the Criterion menu to select the information criterion to use: -2LL, AIC, BIC.
The best scenario based on the criterion (-2LL, AIC, or BIC) is selected in the Scenarios sub-tab (in the Parameters tab). The selected scenario is used for any subsequent Simple runs. An example of a selected scenario that was created after using the covariate search stepwise mode is shown below.
Covariate Search Shotgun searches only generate the Overall worksheet as an output worksheet. To generate the full results, change the Run Mode to Scenarios and re-execute. Since the best scenario (based on the criterion -2LL, AIC, or BIC) is selected automatically after the covariate search, it will be used during the Scenarios run. The selected scenario is also used for any subsequent Simple runs.