HS GPA and Math Placement

In the policy world, “multiple measures” is the silver bullet for solving all issues of student placement in college.  Within the work of multiple measures, the HS GPA is presented as the most reliable measure related to student placement.  This conclusion is the result of some good research being used for disruptive purposes, where a core conclusion is generalized to mathematics when the data was directed at language (‘english’) placement.

A central reference in the multiple measures genre is the Scott-Clayton report from the CCRC ( https://ccrc.tc.columbia.edu/publications/high-stakes-placement-exams-predict.html ).  One of the key findings in that report is that placement tests have more validity in math than in english.  Other results include the fact that placement accuracy could be improved by including the HS GPA … especially in English.  However, the narrative since that time has repeated the unqualified claim — that HS GPA is a better predictor than placement tests.  Repetition of a false claim is a basic strategy in the world of propaganda.

In an earlier post, I shared a graphic on HS GPA vs ACT tests.

This data is from a large ACT study, which means that … if the GPA was a good predictor … we would see all ACT score ranges have a high probability of passing (B or better) in a college algebra course.  The fact that the two lower ACT ranges have an almost-zero rate of change contradicts that expectation.

Locally, I have looked at HS GPA versus math testing using SAT Math scores:

Although this graph does not look at ‘success’, we have plenty of other data to support the conclusion of Scott-Clayton — math placement tests have better validity than English tests.  [The horizontal reference lines in this graph represent the cutoffs for our math classes.]

One might make the argument that math tests work fine for algebraic-based math courses, and that HS GPA works better for general education math courses.  As it turns out, we have been using a HS GPA cutoff for our quantitative reasoning course (Math119) … which includes some algebra, but is predominantly numeracy.

Results:

• Students who used their HS GPA to place:  44% pass rate
• Students who placed via a math test:  77% pass rate

In fact, I am seeing indications in the data that the HS GPA should be used as a negating factor against placement tests … a score above a cutoff with a low HS GPA indicates a lack of ‘readiness’ to succeed.

In theory, a multiple-measures-formula could include negative impacts (in this case, HS GPA below 3.0).  In practice, this is not usually done.  [Another point:  multiple measures formulas are based on statistical analysis … and politics … which transforms a mathematical problem into statistics resulting in a ‘formula score’ which has no direct meaning to us or our students.  An irony within this statistical work is that the HS GPA lacks the interval quality needed to use a mean: the HS GPA itself is a bad measure, statistically.]

Regardless of formulas for multiple measures, we have sufficient data to conclude that HS GPA is well correlated with general college success as well as readiness in English but that HS GPA has little independent contribution in measuring math readiness.

Mathematics placement should be a function of inputs with established connections to mathematics.  The results should be easy to interpret for our students.  Any use of the HS GPA in mathematics placement violates principles of statistics and also contradicts research.

No Comments

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a comment

You must be logged in to post a comment.