I’m happy to announce that version 0.8.0 of my ggeffects-package is on CRAN now. The update has fixed some bugs from the previous version and comes along with many new features or improvements. One major part that was addressed in the latest version are fixed and improvements for mixed models, especially zero-inflated mixed models (fitted with the glmmTMB-package).
In this post, I want to demonstrate the different options to calculate and visualize marginal effects from mixed models.
Weiterlesen „ggeffects 0.8.0 now on CRAN: marginal effects for regression models #rstats“
ggeffects (CRAN, website) is a package that computes marginal effects at the mean (MEMs) or representative values (MERs) for many different models, including mixed effects or Bayesian models. One of the advantages of the package is its easy-to-use interface: No matter if you fit a simple or complex model, with interactions or splines, the function call is always the same. This also holds true for the returned output, which is always a data frame with the same, consistent column names.
The past package-update introduced some new features I wanted to describe here: a revised
print()-method as well as a new opportunity to plot marginal effects at different levels of random effects in mixed models…
Weiterlesen „Marginal Effects for (mixed effects) regression models #rstats“
Regression coefficients are typically presented as tables that are easy to understand. Sometimes, estimates are difficult to interpret. This is especially true for interaction or transformed terms (quadratic or cubic terms, polynomials, splines), in particular for more complex models. In such cases, coefficients are no longer interpretable in a direct way and marginal effects are far easier to understand. Specifically, the visualization of marginal effects makes it possible to intuitively get the idea of how predictors and outcome are associated, even for complex models.
The ggeffects-package (Lüdecke 2018) aims at easily calculating marginal effects for a broad range of different regression models, beginning with classical models fitted with
glm() to complex mixed models fitted with lme4 and glmmTMB or even Bayesian models from brms and rstanarm. The goal of the ggeffects-package is to provide a simple, user-friendly interface to calculate marginal effects, which is mainly achieved by one function:
ggpredict(). Independent from the type of regression model, the output is always the same, a data frame with a consistent structure.
Weiterlesen „Marginal Effects for Regression Models in R #rstats #dataviz“