More Teachers ≠ More Learning

The Dogwood are coming into bloom so we can expect VDOE to start posting the data they have had since last September.  Indeed, they posted Table 17b, “Instructional Positions Per 1,000 ADM,” the other day.

A reader (the reader?) noticed and asked whether there is a relationship between those numbers and the SOL pass rates.  The short answer is “no.” 

The longer answer:

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The fitted line might suggest that increasing the relative number of teachers is associated with decreasing pass rates but the minuscule R-squared value tells us that the two variables are essentially uncorrelated.

The gold square is Richmond; the red diamonds, from the left, are the peer cities, Newport News, Hampton, and Norfolk.  Lynchburg (home of the reader) is blue; Charles City, green.

Using the same system, here are the data for the other four subject areas.

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And here is the five subject average.

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I will resist the temptation to comment further about Richmond’s above-average number of teachers and it’s bottom-of-the-barrel pass rates.  (I earlier discussed Richmond’s very expensive failure rates and dismal graduation rates.)