"X Months of Learning" Is a Phony Metric
Arne, how many months of student learning is that?
OK, a little hyperbolic on the headline, but now that I've got your attention...
I've been reading more and more studies these days that attempt to illustrate gains in "student achievement" in ways that lay people can understand. One of the most common methods I've seen is to translate test score gains into this phrase: "x months of learning." Matt DiCarlo points us to a classic example: Eric Hanushek's assertion that the difference between a "good" teacher and a "bad" teacher is a "year of learning":
I've been reading more and more studies these days that attempt to illustrate gains in "student achievement" in ways that lay people can understand. One of the most common methods I've seen is to translate test score gains into this phrase: "x months of learning." Matt DiCarlo points us to a classic example: Eric Hanushek's assertion that the difference between a "good" teacher and a "bad" teacher is a "year of learning":
So, here’s the deal (and this is strictly my opinion): There is a research consensus that estimated test-based teacher effects vary widely between the top and bottom of the distribution, but the “year and a half” assertion should probably be put out to pasture, at least when it’s used without elaboration or qualification.It implies a precision that belies the diversity of findings within the research literature,
