MODULE 9 – Between-Subjects Factorial Designs

Factorial Design

A research design that includes more than one independent variable to study individual and combined effects.

Factor

An independent variable manipulated in an experiment.

Level

The variations or categories under each factor.

Condition

A unique combination of factor levels in a factorial design.

Main Effect

The effect of one independent variable on the dependent variable, ignoring other variables.

Interaction Effect

Occurs when the effect of one IV depends on the level of another IV.

High-Order Interaction

Interaction involving three or more independent variables.

One-Factor Design

Experimental design with one independent variable.

Two-Factor Design

Experimental design with two independent variables.

Three-Factor Design

Experimental design with three independent variables.

Factorial Notation

A shorthand to show number of levels for each IV (e.g., 2x2, 3x2).

Factor-Labeling Method

Format like 2x2 (Study Method x Time of Day); shows factor names.

Factor and Levels Method

Format like 2x2 (Method: Spaced, Massed x Time: Morning, Evening); includes both factor names and levels.

2x2 Factorial Design

Two independent variables with two levels each, creating four conditions.

Between-Subjects Design

Each participant experiences only one condition.

Why Keep Between-Subjects Simple

To reduce participant needs, avoid complexity, and ensure results are interpretable.

How to Detect Interaction on Graph

If the lines cross or diverge, it indicates interaction.