The pie is based on John Hattie’s analyses of the sources of variance that impact on learning. Both the Best Evidence Synthesis by Adrianne Alton-Lee (2003) and the recent meta-analyses on apportionment of variance shows that the pie is reasonably representative of the various influences. Sometimes the point is missed which is that the largest source of variance we have control over relates to teachers, not schools. And some forget to mention the phrase “that we have control over.” Of course, the pie shows the largest source of variance is among students.
Articles in this section
- Why does the Visible Learning research use effect sizes?
- Why do you use an effect size of d=0.40 as a cut-off point and basically ignore effect sizes lower than 0.40?
- What is the preferred timescale over which an effect size can be calculated?
- Is there a bias when using effect sizes in favor of lower achieving students?
- What caution should I take when calculating an effect size?
- Why are effect sizes used when conducting meta-analysis?
- Why can an effect size of 0.40 be gained in a shorter timeframe?
- Can effect sizes be added (or averaged)?
- How accurate are the conclusions drawn from meta-analysis?
- How can the variability associated with each influence be evaluated?