Title: Towards Easy and Accessible Cognitive Measurement Models: Introducing the Bayesian Measurement Model (bmm) R Package Authors: Gidon T. Frischkorn, Vencislav Popov Abstract: In cognitive individual differences research the use of cognitive measurement models – formal models that describe how latent cognitive processes relate to observed behavior – has become more and more popular to measure individual differences in cognitive processes. Yet, estimating subject-level parameters for such models flexible in different study designs is challenging and often requires researchers to have advanced knowledge in cognitive modeling and state-of-the art statistical estimation methods. In this talk, I will introduce the Bayesian Measurement Models (bmm) package for R. This package implements commonly used cognitive measurement models in a hierarchical Bayesian framework building upon the Bayesian Regression Models using Stan (brms) package. The benefit of using brms as a backend, is that its powerful linear model syntax allows to estimate the implemented models in basically any study design. To date, the bmm packages includes mainly measurement models for memory processes, in the discussion I will outline further models that we plan to include in the future and would appreciate input on models that would be of great interest to a broad range of researchers.