/categories/bayesian-estimation/ Recent content in Bayesian estimation on Nils Myszkowski, PhD Hugo -- gohugo.io en Sun, 23 Feb 2025 00:00:00 +0000 /publications/2025-bayesian-log-linear-poisson-irt-brms-stan/ Sun, 23 Feb 2025 00:00:00 +0000 /publications/2025-bayesian-log-linear-poisson-irt-brms-stan/ What it’s about In this paper, we present a Bayesian estimation workflow for generalized log-linear Poisson item-response models applied to fluency scores in divergent-thinking assessment, with practical implementation using brms and Stan. Abstract Divergent-thinking tests often rely on fluency scores (counts of ideas generated per prompt), and these counts can be modeled with Poisson item-response models. This paper revisits the Rasch Poisson Counts Model and its generalized two-parameter extension (2PPCM), and shows how both can be estimated in a Bayesian multilevel regression framework through brms (Stan backend).