Monday, January 31, 2011

ACT: Not the Only Measure of College Readiness

Council on Postsecondary Education honcho Bob King recently argued in the Herald-Leader that CPE's High School Feedback Report allows the state "to look more deeply into actual performance measured by an external, unbiased resource — the ACT exam."

King suggested that the ACT, by itself, was superior to predictions of college-readiness derived from combinations of data. Discounting graduation rates and average GPA in favor of a single test prompted our resident testing expert to retort.

NOTE: H-L seemed to struggle editing Skip's piece, so here's the unadulterated article the paper titled:

If I were to assert that a player who cannot make 56% of his free throws is not "ready" for the NBA, a fan would point out that there is much more to basketball than shooting free throws. An astute fan with a historic prospective would point out that Wilt Chamberlain, Shaquille O'Neal and a bevy of other current players would not be "ready" using that arbitrary standard. One facet of basketball does not make or break a player's "readiness."

Bob King, president of Kentucky's Council on Postsecondary Education, in a recent op-ed piece applies the council's arbitrary standard of using a single test score to determine whether a student is "ready" for regular course work in Kentucky's public universities. He implies a test score is a better predictor of grades in college than is a high school record. He then presents results from one high school that lump higher performing students (those with above average high school records) with lower performing ones in a misguided approach to justify his position. A test score, however, does not make or break a student's "readiness" for higher education.

Decades of research indicate: performance in academic courses in high school is the single best predictor of success in higher education; a combination of the high school record and test scores predict better than the high school record alone; and, how good the prediction is and how the components are combined vary depending on the institution. Although there is a general pattern of the primacy of the high school record, there is no one-fits-all model to predict grades in different courses or different institutions.

In addition to the thoroughly suspect notion of labeling a test score readiness, the council's use of a single score for placement purposes violates standards for the proper use of tests. Those standards include the following:

In educational settings, a decision or characterization that will have major impact on a student should not be made on the basis of a single test score. Other relevant information should be taken into account if it will enhance the overall validity of the decision.

In addition:

When test scores are intended to be used as part of the process for making decisions for educational placement, promotion, or implementation of prescribed educational plans, empirical evidence documenting the relationship among particular test scores, the instructional programs, and desire student outcomes should be provided. When adequate empirical evidence is not available, users should be cautioned to weight test results accordingly in light of other relevant information about the student.

Apparently, the council determines readiness by doing statistical analyses of ACT scores and grades in first year courses without regard to institution. A certain ACT score produces a 50/50 chance of getting certain grades, say C, or better. I could find no information about this or other investigations done by the council. And, although it is possible to present information about how good a model is, I could not find any information of that kind either.

To give a sense of the power of statistical models to predict first year grades I report analyses conducted years ago on University of Kentucky student samples. The question was whether results of KIRIS, the first commonwealth assessment related to school reform, could be used for admission and placement in a university.

If a model exactly predicts grades one can say that the model accounts for 100 % of what could be known. If a model cannot at all predict grades, one can say that 0% is accounted for. One way, then, to talk about the power of a statistical model is determine what percent the model predicts.
The table below gives those percents for different courses at UK for three different statistical models: High school record only, High School record + ACT scores and High School record + KIRIS scores.

The first thing to recognize is that the models are not particularly powerful. They rarely account for 25% of what could be known leaving 75% to be explained. That 75% may be differences in students' study habits, class attendance, interests, any of a thousand other variables or simply things not explained statistically.

The pattern of results, however, is clear. Adding an ACT score to a model containing GPA makes the prediction better but not greatly so. The same is true for KIRIS scores, too. Incidentally, that was without including the KIRIS writing sample.

These are not unusual results. They point, obviously, to gathering more information about a student before making a placement decision. Here is what ACT says:

ACT offers a variety of tools to ensure postsecondary students are quickly and accurately placed in courses appropriate to their skill levels. Assessment tools from ACT offer a highly accurate and cost-effective basis for course placement. By combining students' test scores with information about their high school coursework and their needs, interests, and goals, advisors and faculty members can make placement recommendations with a high degree of validity.

To that, I would add, for obvious reasons, it is desirable for an educational agency to use tests in exemplary ways.

The op-ed piece goes on to exhort parents to ask right questions, asks an undefined "we" to fear international test results, says admissions offices should align themselves with the council's readiness standards, and the still undefined "we" to serve teachers more effectively. Such exhortations would be more convincing if, in the first instance, the council could propose placement procedures based on a robust notion of "readiness" that in addition did not violate test score use standards.

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