MANOVA

TL;DR

• Tests group or treatment effects on multiple dependent variables at once.
• Commonly used in experimental research to compare groups across several outcomes.
• Gives a more comprehensive view than separate ANOVAs and can reveal interactions among dependent variables.

Definition

MANOVA, or Multivariate Analysis of Variance, is a statistical method used to evaluate the relationship between two or more dependent variables and one or more independent variables.

Explanation

MANOVA is often applied in experimental research to determine whether levels of an independent variable produce significant differences across multiple dependent variables. Researchers collect measurements for each dependent variable from each subject (or experimental unit) and use MANOVA to assess whether group differences exist jointly across those outcomes. Compared with separate ANOVAs, MANOVA evaluates multiple dependent variables simultaneously, providing a broader view of the independent variable’s effects and allowing detection of potential interactions among the dependent variables.

Examples

Drug study

A study examining the effects of a new drug on blood pressure and cholesterol levels in a group of participants. The independent variable is the administration of the new drug, and the dependent variables are blood pressure and cholesterol levels. The researcher collects data on both dependent variables for each participant and uses MANOVA to determine if there are significant differences in blood pressure and cholesterol levels between the group that received the new drug and the control group that did not.

Parenting program study

A study examining the effects of a parenting program on children’s academic achievement and behavior in school. The independent variable is participation in the parenting program, and the dependent variables are academic achievement and behavior in school. The researcher collects data on both dependent variables for each child and uses MANOVA to determine if there are significant differences in academic achievement and behavior in school between the group of children who participated in the parenting program and the control group who did not.

Use cases

• Experimental research comparing groups or treatment levels on several outcome measures simultaneously.

Notes or pitfalls

• Assumptions of normality and homogeneity of variance must be met for reliable results.
• MANOVA can be computationally complex and may require advanced statistical software and expertise to analyze properly.

Related terms

• ANOVA
• Independent variable
• Dependent variable