How to Report a Two-Way ANOVA in APA 7 (With Example)

A two-way (factorial) ANOVA tests the effect of two categorical independent variables on one continuous outcome, and crucially whether they interact. The write-up is longer than a one-way ANOVA because you report two main effects plus the interaction, each with its own F statistic and effect size. This guide gives you the exact APA 7 format, a worked example you can copy, and the mistakes reviewers catch.

What you need before you write a single word

An APA 7 write-up of a two-way ANOVA needs, for each of the three effects (Factor A, Factor B, and the A by B interaction):

1. The F value.
2. Two degrees of freedom (effect df and error df).
3. The exact p value.
4. An effect size, usually partial eta squared.

You also need the cell means and standard deviations (each combination of the two factors), best shown in a table.

The APA 7 format template

Report each effect in running text. The interaction is the most important, so lead with whether it was significant:

A two-way ANOVA showed a significant main effect of [Factor A], F(df, df_error) = X.XX, p = .XXX, partial eta-squared = .XX, and of [Factor B], F(df, df_error) = X.XX, p = .XXX, partial eta-squared = .XX. The [Factor A] by [Factor B] interaction was [significant/not significant], F(df, df_error) = X.XX, p = .XXX, partial eta-squared = .XX.

Formatting rules reviewers actually check:

• Report both degrees of freedom for every F: effect df first, then error df.
• No leading zero on p or partial eta squared.
• Round F to two decimals. If p is below .001, write p < .001.
• If the interaction is significant, interpret it (often with simple-effects tests), because it qualifies the main effects.

A worked example

Suppose you tested the effect of teaching method (lecture vs flipped) and study time (low vs high) on exam scores, with 20 students per cell.

• Main effect of method: F(1, 76) = 9.84, p = .002, partial eta-squared = .11
• Main effect of study time: F(1, 76) = 18.30, p < .001, partial eta-squared = .19
• Interaction: F(1, 76) = 5.12, p = .027, partial eta-squared = .06

Written up in APA 7, that becomes:

A two-way ANOVA showed a significant main effect of teaching method, F(1, 76) = 9.84, p = .002, partial eta-squared = .11, and of study time, F(1, 76) = 18.30, p < .001, partial eta-squared = .19. These were qualified by a significant method by study-time interaction, F(1, 76) = 5.12, p = .027, partial eta-squared = .06. Simple-effects tests showed that the flipped classroom advantage was larger for high-study-time students than for low-study-time students.

The APA 7 cell-means table

A two-way design needs a table of cell means and SDs. APA tables use horizontal rules only:

Note. Exam scores range from 0 to 100. n = 20 per cell.

Mistakes reviewers catch

• Ignoring the interaction. The interaction is often the whole point of a factorial design. Always report it, and if it is significant, interpret the main effects in light of it.
• Reporting only one degree of freedom. Every F needs both, effect and error: F(1, 76).
• Using eta squared instead of partial eta squared. In factorial designs, partial eta squared is the conventional effect size.
• No cell means. The reader needs the mean for each combination of factors, not just the F statistics.
• Writing p = .000. Report p < .001.
• A leading zero on p or partial eta squared. APA drops it.

Before you report: did the model's assumptions hold?

A two-way ANOVA assumes:

• Independence of observations.
• Approximate normality of the outcome within each cell.
• Homogeneity of variance across cells (Levene's test).

Roughly equal cell sizes make the test more robust to violations. For a single factor, see our guide on reporting a one-way ANOVA.

Let KyroStat do the write-up for you

Formatting a factorial ANOVA, with two main effects, an interaction, partial eta squared, and a cell-means table, is where errors creep in. KyroStat runs the two-way ANOVA on your data, tests the interaction and simple effects, checks the assumptions, and hands you the finished APA 7 sentences, the cell-means table, the plot, and the underlying Python or R code. Upload your spreadsheet, and the report is done in seconds.

Frequently asked questions

What makes a two-way ANOVA different from a one-way ANOVA? A one-way ANOVA has one factor. A two-way ANOVA has two factors and also tests their interaction, whether the effect of one factor depends on the level of the other.

Which effect size should I report? Partial eta squared for each main effect and the interaction, reported without a leading zero.

What if the interaction is significant? Interpret the main effects cautiously and run simple-effects tests to describe how one factor's effect changes across levels of the other.

My p value shows as .000. What do I write? Report p < .001. A p value is never exactly zero.