afex: Functions for Factorial Experiment Analysis in R

afex is an R package providing convenience functions for analyzing factorial experiments. It supports ANOVA and mixed models for between-subjects, within-subjects, and mixed designs, automatically aggregating data in long format. The package, authored by Henrik Singmann, includes functions for model fitting and high-level plotting with ggplot2.

Use Cases

• Conducting repeated-measures ANOVA based on the aov_ez() function for within-subject designs.
• Fitting linear mixed models using the mixed() function with p-value approximations for fixed effects.
• Creating interaction plots for factorial designs based on the afex_plot() interface to ggplot2.
• Analyzing split-plot experimental designs using the aov_4() function for mixed between/within factors.

Strengths

• Provides a unified interface for ANOVA and mixed model analysis, simplifying workflow.
• Automatically aggregates multiple observations per individual and design cell for data in long format.
• Includes high-level plotting functions that combine raw data with model estimates.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Row count and column definitions are unknown, which may limit suitability assessment.
• Uses Type III sums of squares as a default, which may not be appropriate for all experimental designs.

Provenance

Source

Henrik Singmann

Collection Method

Software package for statistical analysis.