It All Measures Up!

By Dan Helms

By now, all adult educators in Indiana have heard about the new high-school equivalency assessment instrument that, as of January 1st, replaced the GED®. The Tests Assessing Secondary Completion, or TASC, is published by CTB/McGraw-Hill. As with the previous versions of the GED® that were used for this purpose, the TASC is a norm-referenced test. So, what is a norm-referenced test, and what does it mean to pass such a test?

A norm-referenced test is a standardized assessment, in which all students perform under the same conditions. This type of test compares a student or group of students with a specified reference group, usually others with similar characteristics such as those in adult basic education classes. Passing TASC means that a person has proven he or she has learned and can do as much or more than 40 percent of seniors who graduate from high school. That’s why TASC is called an equivalency test, since it shows that what a test taker knows is equal to at least 40 percent of what a person with a high school diploma knows, as demonstrated by the same test.

As we compare TASC scores of all test takers, these scores, intentionally, can be mapped onto the well-known “Bell-Shaped Curve.” There will be some scores on the low end of the curve, some scores on the high end, and the majority of the scores will be clustered in the middle. This is known as a “normal distribution,” and is associated with norm-referenced testing. The goal of norm-referenced testing is to rank the set of candidates’ scores so that generalized predictions can be made about the candidates’ chances for success. In this case, success is viewed as one’s likelihood of being capable to enter a college or career pathway and steadily progress.

The TASC should not be confused with criterion-referenced tests (CRT). CRTs differ in that each examinee’s performance is compared to a pre-defined set of criteria, such as academic standards. The goal with these types of tests is to determine whether or not a test taker has demonstrated mastery of a skill or set of skills. Students usually either pass or fail a CRT. Passing could have favorable outcomes, including job entry, career certification, or earning a license. But remember, the students taking such a test will not be compared to the performance of other test takers. Rather, their performance is being compared to a pre-defined set of criteria.

What this all means, if you’ll pardon my saying it, is that a candidate could pass the TASC without having mastered 100% of the standards it is assessing. Again, to pass the norm-referenced TASC, a candidate must perform as well or better than 40% of the high school graduates, to whom the candidate is being compared, performed on the same test. There’s no clearly defined percentage of the content standards that a student must master in order to pass the TASC, because that would only be true if this test were criterion-referenced.

Going back to what I learned while studying mathematics in college, I could explain how a normal distribution is calculated by first finding the arithmetic mean (μ) of the data set, then the standard deviation (σ), then using the following defined function for a normal distribution:

Instead, let me wrap this up by simply saying that a comparison study was performed by CTB/McGraw-Hill to develop a normal distribution of the TASC scores of the reference group. I don’t have access to these scores, or the normal distribution of this data, but it’s enough to know that the distribution must look like:

In conclusion, I’m suggesting that students are going to be successful at passing the TASC. As we move forward, we’ll all learn more about what they most need. As we learn more, the instructional practices will be adapted. As instruction changes, scores will improve and even more candidates will pass. So take a deep breath, remain calm, and keep teaching. I know you’re all up to the TASC.

Dan Helms
McGraw-Hill Contemporary
BS, MS – Mathematics; MA – Secondary Mathematics Education