Table 4.
Step | Description | Recommendation | Presentation | |
---|---|---|---|---|
Interpreting Final Model | Convergence | A form of internal validation where the maximum likelihood for each model is generated using random starts. | - Multiple random starts are recommended (minimum 50) to replicate the maximum likelihood at least 20 times. - Increase number of starts with models with increased complexity.(55) - If likelihoods are not replicated evaluate data structure and type. Consider rejecting model if maximum likelihoods are not rejected. |
- Confirm that maximum likelihood was replicated at least 20 times for all models in the analysis - Presenting the maximum likelihood is optional as the AIC and BIC are generated using this value |
Classification | Probabilities generated by the model are used to classify each observation to a class. | - Probabilities cut-offs to assign class should be determined a priori. - If the entropy of the model is low with poor class separation, the uncertainty of class membership should be incorporated in the analysis. |
- Present the probability distribution of the classes in the optimal model that best describes the population (final model). | |
Salsa Effect | This refers to the coercion of classes to fit a population that may not have latent classes. | - Examine the distributions of the indicator variables to see if they suggest a single population has been spread out along a continuum. | - Not applicable. | |
Outcome Measures | To demonstrate that the identified classes are of value, certain key variables are shown to differ between the classes. | - A priori key discriminant outcome measures should be described in the analysis plan. - Investigators should be blinded from these outcome measures when determining the best fitting model. |
- An a priori analysis plan should describe the likely metric that will be used to determine differences between the latent classes and gauge their clinical utility. |