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. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Crit Care Med. 2021 Jan 1;49(1):e63–e79. doi: 10.1097/CCM.0000000000004710

Table 4.

Summary of key steps and recommendations when interpreting the final model.

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.