The Open UniversitySkip to content

Eta squared and partial eta squared as measures of effect size in educational research

Richardson, John T. E. (2011). Eta squared and partial eta squared as measures of effect size in educational research. Educational Research Review, 6(2) pp. 135–147.

DOI (Digital Object Identifier) Link:
Google Scholar: Look up in Google Scholar


Eta squared measures the proportion of the total variance in a dependent variable that is associated with the membership of different groups defined by an independent variable. Partial eta squared is a similar measure in which the effects of other independent variables and interactions are partialled out. The development of these measures is described and their characteristics compared. In the past, the two measures have been confused in the research literature, partly because of a labelling error in the output produced by certain versions of the statistical package SPSS. Nowadays, partial eta squared is overwhelmingly cited as a measure of effect size in the educational research literature. Although there are good reasons for this, the interpretation of both measures needs to be undertaken with care. The paper concludes with a summary of the key characteristics of eta squared and partial eta squared.

Item Type: Journal Item
Copyright Holders: 2011 Elsevier Ltd.
ISSN: 1747-938X
Keywords: effect size; eta squared; partial eta squared
Academic Unit/School: Faculty of Wellbeing, Education and Language Studies (WELS)
Research Group: Centre for Research in Education and Educational Technology (CREET)
Item ID: 26053
Depositing User: John T. E. Richardson
Date Deposited: 05 May 2011 10:58
Last Modified: 01 May 2019 11:37
Share this page:


Altmetrics from Altmetric

Citations from Dimensions

Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU