I published a blog post late last month questioning the numbers in a recent paper on teacher shortages from the Learning Policy Institute (LPI). After speaking with Linda Darling-Hammond, one of the report’s authors, and reading their written rebuttal, I have a clearer sense of what they did and why their numbers seemed off to me.
From what I can tell, our disagreement centers on their definition of the word “supply.” Their report says this:
In this report, we use a theoretical framework of supply and demand that defines a teacher shortage as an inadequate quantity of qualified individuals willing to offer their services under prevailing wages and conditions.
The last part is key. What they mean by “individuals willing to offer their services under prevailing wages” essentially means “people who will be hired as teachers.” They have no data on job applicants or anyone’s desire or willingness to teach. They do attempt to include people who delay entry into the teaching profession, but their assumptions lead them to exclude almost all of the people who train to become teachers who never land a teaching job.
This is a questionable definition, and it leads to some weird conclusions. Continue reading