Diploma Inflation?

The estimable Jim Bacon the other day raised the question whether Virginia’s increasing graduation rates might be related to grade inflation.

We have some data on a nearly-related subject:  Recall that the standard diploma requires five “verified credits” (i.e., passing the course plus passing End of Course (“EOC”) SOLs or approved substitute tests) in English, math, laboratory science, and history & social science, (Added note): plus one in a subject of the student’s choice (presumably in one of those five areas) (Hat Tip, the illustrious Chuck Pyle).  The advanced diploma requires three further verified credits.

The VDOE Web site has the Virginia average 4-year cohort graduation rates (back to 2008) along with the End of Course pass rates.  Here are the diploma rates along with the reading pass rates:

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Hmmm.  Looks like the pass rate declined slowly through 2012, dropped a bit with the new (harder) tests in 2013, and remained about flat afterward.  During this time, the graduation rate with standard diplomas remained close to 35% while the rate of advanced diplomas rose from 44% to 52%, both with no dip in 2013.

Since Excel already has the data, let’s look at the correlations.

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The writing tests tell much the same story.

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That’s English.  How about math?

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Here the new tests in 2012 had a large effect on the pass rate but the advanced diploma rate still rose unimpeded.  The (negative!) correlations are substantial:

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Well, how about History & Social Science?

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Finally, science.

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Whatever is going on here – and the process is so byzantine that an outsider might despair to understand it – it is clear that the average graduation rate, especially of advanced diplomas, is not constrained by the EOC pass rates.  If anything, the graduation rates and pass rates are going in different directions.

Bacon mentions grade inflation.  This looks like diploma inflation somewhere outside the verified credit process.

Note added July 26: Here is a summary graph with all the data:

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