Category Archives: Statistics

Reliability and VAM

One of the problems of using value-added measurement (‘VAM’) to assess individual teachers is the imprecision of these estimates. Brad Lindell explains the problem in testimony in a New York case challenging teacher assessment: If the same test-retest reliability from … Continue reading

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How You ‘Pre-Treat’ Your Data Really Matters (It’s Not the P-Hacking)

There’s an 538 article “Science Isn’t Broken” that’s winding its way through the tubes of the internet. It has a cool ‘p-hacking’ interactive feature, which is probably why most of the associated commentary has focused on the problem of p-hacking … Continue reading

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VAM-Based Teacher Evaluation Collides With the Legal System

And if the judge’s questions are any indication, VAM-based teacher evaluation gets hit and dragged a couple hundred yards (boldface mine): Lederman’s suit against state education officials — including John King, the former state education commissioner who is now a … Continue reading

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Understanding the Limitations of Your Data: At-Risk Versus Low-Income

A while ago, I described how decisions about how to treat your data can have significant effects on your results–effects that can be as profound as, if not greater than, p-value tweaking. So a preliminary analysis of the effects of … Continue reading

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IMPACTing D.C.’s Teachers

This won’t help D.C.’s schools (boldface mine): I worked in a school for students who struggled in mainstream classroom environments due to emotional or behavioral issues, but I had managed to figure out a way to reach them and make … Continue reading

Posted in DC, Education, Statistics | 1 Comment

A Visual Image of What “Understand the Limitations of Your Data” Means

One of the things I’ve repeated on this blog a few times is people have to like this crap you have to understand the limitations of your data. In a good Nature piece about how the problems with using p-values … Continue reading

Posted in Genomics, Statistics | 1 Comment

Being VAMbushed By Weapons of Math Destruction

There’s some very interesting public testimony by Luke Flynt, a Florida English teacher. At the end of the post, I’ve included the video–it’s short and very clear (maybe because Flynt is a professional teacher. Just saying). But his testimony about … Continue reading

Posted in Education, Statistics | 2 Comments