Gene V Glass: Education in Two Worlds: How Much Academic Growth?

Gene V Glass: Education in Two Worlds: How Much Academic Growth?

How Much Academic Growth?

Recently, a colleague in England very politely called me on the carpet for something I wrote in 1981 that did not mercifully die in the interim. Here is his question.

Dear Dr. Glass As you may know, the Education Endowment Foundation in England, in order to help with interpreting effect sizes in education, has suggested to teachers that an effect size of one standard deviation is approximately equal to one year’s progress, and they cite the following from page 103 of your 1981 book ‘Meta-analysis in education’ in support:

It is also known, as an empirical—not definitional—fact that the standard deviation of most achievement tests in elementary school is 1.0 grade-equivalent units; hence the effect size of one year’s instruction at the elementary school level is about +1, for example,

∆ = (4.0 - 3.0) / 1.0 = +1.

I asked one of your co-authors, Barry McGaw (whom I know well) if he could recall where this figure came from and he could not, hence this email to you.The reason I ask is that for many of the tests currently in use in CONTINUE READING: 

Gene V Glass: Education in Two Worlds: How Much Academic Growth?