Accounting for Variable Task Discrimination in Divergent Thinking Fluency Measurement – An Example of the Benefits of a 2-Parameter Poisson Counts Model and its Bifactor Extension Over the Rasch Poisson Counts Model

In this paper, we introduce new psychometric models for count/fluency tasks (tasks in which individuals have to provide many instances). Notably, we extent the Rasch Poisson Counts Model (RPCM) to account for variable discrimination (2-Parameter Poisson Counts Model) and to account for local dependencies/nuisance factors (Bifactor 2-Parameter Poisson Counts Model).