The finding that at least two-thirds of the factors influencing student test scores are outside of a teacher’s control is well-researched and pretty commonly accepted. You can find all that research at The Best Places To Learn What Impact A Teacher & Outside Factors Have On Student Achievement.

Today, I saw this tweet that provides an excellent visual of those findings:

As the tweet says, it comes from a report by Edward H. Haertel, emeritus professor of education at Stanford. The report was published by Educational Testing Service.

I previously posted
about a talk Professor Haertel gave on his report, which included a video, but didn’t highlight this particular pie chart.

In case you missed it, here’s a quote from his talk that I highlighted in that post: