Contrasts

Analysis of main effects, simple effects, interaction effects, partial interaction effects, and nested effects

Comparisons against reference groups, of adjacent levels, or against the grand mean

Orthogonal polynomials

Helmert contrasts

Custom contrasts

ANOVA-style tests

Contrasts of nonlinear responses

Multiple-comparison adjustments

Balanced and unbalanced data

Contrasts in odds-ratio metric

Contrasts of means, intercepts, and slopes

Graphs of contrasts

Interaction plots

Watch Introduction to contrasts in Stata: Oneway ANOVA.

 

Pairwise comparisons

Compare estimated means, intercepts, and slopes

Compare marginal means, intercepts, and slopes

Balanced and unbalanced data

Nonlinear responses

Multiple-comparison adjustments: Bonferroni, Šidák, Scheffé, Tukey HSD, Duncan, and Student–Newman–Keuls adjustments

Group comparisons that are significant

Graphs of pairwise comparisons

 

Marginal analysis

Estimated marginal means

Marginal and partial effects

Average marginal and partial effects

Least-squares means

Predictive margins

Adjusted predictions, means, and effects

Works with multiple outcomes simultaneously

Contrasts of margins

Pairwise comparisons of margins

Profile plots

Graphs of margins and marginal effects

 

Additional resources

In the spotlight: How do you compare? Examining effects in multilevel models using contrasts

In the spotlight: Estimating, graphing, and interpreting interactions using margins

In the spotlight: Visualizing continuous-by-continuous interactions with margins and twoway contour