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Re: effect size: eta-squared vs partial eta-squared

Posted by Burleson,Joseph A. on Jul 18, 2006; 8:24pm
URL: http://spssx-discussion.165.s1.nabble.com/effect-size-eta-squared-vs-partial-eta-squared-tp1069749p1069756.html

Just to clarify:

Cohen's rules of thumb that you list are for mean differences (t-tests,
etc.) translated into r-sq. But his section on correlation uses small
(r = .10, r-sq = .01), medium (r = .30, r-sq = .09), and large (r = .50,
r-sq = .25). He then rectifies these discrepancies on pp. 81-82 (in the
1977 edition, sorry--don't have the '88 at hand, but the chapter on r).

As to your question of partial et-sq and r-sq, I would be curious to any
responses since I always assumed that the interpretation of the effect
size of one would be equivalent to the other.

Joe Burleson

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Dogan, Enis
Sent: Tuesday, July 18, 2006 12:55 PM
To: [hidden email]
Subject: effect size: eta-squared vs partial eta-squared

Dear all



SPSS reports partial et-sq as opposed to eta-squared.

I found in the literature the rule thumb for eta-squared as small
(0.01), medium (0.06), and large (0.14) (Cohen, 1988).

Does this apply to partial eta-squared as well?

Also, the definition of eta-squared gives me the idea that it is no
different than what some of us call partial R squared.

Am I right?



There is rumor out there that "researchers erroneously report partial
eta-squared values as representing classical eta-squared values"

http://carbon.cudenver.edu/~haguinis/APMinpress.pdf



Any value in this argument?



Thanx



Enis