
Question: Remembering that Hattie said only an effect size of 0.4 or greater was worth considering (as almost every initiative in education makes *some difference), I'm trying to determine how to read scientific reports to determine this. In this report (http://onlinelibrary.wiley.com/doi/10.1111/j.14698749.2010.03661.x/full) am I right in thinking that none of the results have an effect size that comes anywhere near this, despite the causal claims made?
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Richard commented on :
Correction – higher than* not higher that
Abena commented on :
Thank you Richard. That helps a lot in terms of making the numbers mean something concrete. And good advice about looking at related studies – that’s super helpful for me (and other interested teachers) moving forward.
Abena commented on :
@Courtney – if you have any accessible links for teachers to understand standard deviation that would help. The issue is translating it into something most teachers (nonresearchers) would understand. Thanks so much for giving us some starting points for further learning.
Courtney commented on :
Hi Abena,
Sure!
I think the writeup on this page (http://www.shankerinstitute.org/blog/whatstandarddeviation) does a nice job of introducing the concept of standard deviation and how it relates to interpreting effect sizes, with an example in education. I think it also does a nice job of touching on some points made above about interpreting effect size carefully and thinking about context.
For folks who want more, there is a video on Khan Academy (https://goo.gl/6wdzAU) that goes through an introduction to what standard deviation is and then walks through an example of how to calculate it (which can be helpful in thinking about what it is). I hope this helps!