Why colleges should track credits to graduation, not time to graduation

Let me make four obvious statements:

1. Improving graduation rates is essential for colleges, for society, and for individual students;
2. The current measures--particularly time-to-graduation and 4-year graduation rates--describe things that are, to some significant extent, out of the hands of colleges;
3. Because they are out of the hands of colleges, campus efforts to improve graduation rates get mired in debates about measurement, or frustration at the futility of trying to change something over which we have little control;
4. Such a sense of futility impedes our ability to improve.

So in lieu of time-to-graduation, or 4-year graduation rates, let me propose that colleges measure their effectiveness through credits-to-graduation.  There are a couple of obvious benefits to this measure:

• All schools mandate a minimum number of credit hours to graduation
• Credit hours to graduation describes something over which campuses have significant control
• The measure is comparable across campuses (at least when expressed as a proportion, i.e that students at college Y require 1XX% of their minimum credit hour requirement in order to graduate.)
• The credit hour measure ties directly to the cost for students, since they pay by the credit hour, not by the year.