Tests in medicine and public schools: What do they really measure?

Humans are social creatures who naturally evaluate where they stand in relation to those around them. I have no idea how this evaluation process evolved, but at some point we noticed that some cavemen brought more food to the cave than others. The idea was born that some people are better hunters than others. We’ve been trying to decide who is “better” ever since.

The origin of the word “test” comes from Middle English, and referred to a vessel in which metals were assayed. That is, the test determined what kind of metal was present in the vessel. So a test functioned as an identifier, similar to the way certain medical tests identify specific bacteria. Today most people, when they hear they are being tested, don’t think about the test as just a source of information. People think of testing in terms of evaluation or comparison, a judgement about some aspect of their knowledge or abilities. Someone is better, and someone else is worse.

Here is how Merriam-Webster defines test:

  1. A critical examination, observation, or evaluation.
  2. The procedure of submitting a statement to such conditions or operations as will lead to its proof or disproof or to its acceptance or rejection.
  3. A basis for evaluation.
  4. An ordeal or oath required as proof of conformity with a set of beliefs.
  5. A procedure, reaction, or reagent used to identify or characterize a substance or constituent.
  6. Something (as a series of questions or exercises) for measuring the skill, knowledge, intelligence, capacities, or aptitudes of an individual or group.

Notice the terms “critical,” “ordeal,” “measuring,” “evaluation.”

We have tests for everything. And people are getting sick of tests. Observe the growing backlash against public school testing in New York. Observe the questions arising about medical testing. Observe the pushback from physicians over maintenance of certification exams.

Some tests are good, right? A blood test to identify HIV is good. Quizzing yourself after reading a difficult passage in a textbook is a good test. Covering up the multiplication tables and seeing how much you can do by memory is a good test. Testing the gem in your engagement ring to make sure it’s diamond and not cubic zirconium is a good test. What makes a good test? The Center for Public Education says that test should be “valid, reliable, and free of cultural bias.” Essentially, a good test reliably measures what you want to measure, and, presumably, doesn’t measure what you don’t want to measure.

Let’s take an example. The PSA test evaluates the blood for a prostate-specific antigen that, in high amounts, can be an indicator of prostate cancer. So it measures PSA. That’s all it does. It does not measure how much time a man has left, or mortality rate, or rate of prostate cancer growth, or what the man will eventually die of. In short, it gives you a number that you can’t use. People think a PSA will tell you if you will die of prostate cancer. For that, you’d need a good test. Like a crystal ball.

Here’s another example. Common Core tests kids as early as third grade. The problem with these tests is not that you don’t get useful information. It is that the information you get is not what you want to measure. The test is supposed to measure knowledge but instead tests memorization. It is supposed to measure learning but measures test-taking ability. And actually it isn’t supposed to measure knowledge or learning, but teacher quality. But the test is not administered to teachers, so the test not only doesn’t measure what you want it to but tests the wrong subjects. The result is that students and parents think the test measures the intellect and worth of the student, and school districts think the test measures the intellect and worth of the teacher.

The same problems exist for the maintenance of certification (MOC) exams in anesthesia and other specialties. The tests are time-consuming and expensive and measure memorization and test-taking skills that have nothing to do with quality care.

By some unbelievable miracle, the American Board of Anesthesiology has just announced that they are getting rid of the MOC tests, largely in response to vocal backlash by physicians. Hopefully, a similar outcry from a growing number of parents can effect a similar change in the public schools. It would take a miracle.

Shirie Leng, a former nurse, is an anesthesiologist who blogs at medicine for real.

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