SIMR: an R package for power analysis of generalized linear mixed models by simulation

Summary The r package simr allows users to calculate power for generalized linear mixed models from the lme 4 package. The power calculations are based on Monte Carlo simulations. It includes tools for (i) running a power analysis for a given model and design; and (ii) calculating power curves to assess trade‐offs between power and sample size. This paper presents a tutorial using a simple example of count data with mixed effects (with structure representative of environmental monitoring data) to guide the user along a gentle learning curve, adding only a few commands or options at a time.