The ABCs of Psychometrics… Please Read On!
“I’m an SLP; I was told there would be no math.”
I don’t exactly remember the first time I heard someone say something to this effect—grad school at the earliest, I’m sure—but it has certainly stayed with me and keeps me chuckling as I occasionally think the same thing myself. Ironically, I ended up in a role in the professions where I deal with math and statistics constantly every day in business, development and clinical contexts. Over the years, I also have come to appreciate that there are plenty of places where math and statistics are rightfully embedded in the professions. So where did the “no math” notion come from, I’ve wondered? It certainly isn’t left out of our standard masters-level curriculum.
Lest any young (or seasoned) professional feel encouraged, prodded, or outright pushed into the world of math and statistics against their will, I’d like to call your attention to one of the many critical ways math and statistics need to be on our collective radar as we work daily to improve communication skills in individuals of all ages.
The term of the day is psychometrics. No, it’s not a compound word combining a “psycho” concept with a “metrics” concept exactly! Psychometrics, a subspecialty of psychology, is a discipline that deals with the measurement of human behaviors and/or traits. For our purposes in this article, psychometrics is the discipline of valid and reliable test development.
Excellent test development means you have tools that you can stand behind confidently in your work. The psychometric effort that goes into building a test, among many other areas of expertise, is straightforward yet creative, analytical yet fluid. Psychometricians evaluate the needs that the test fills. They use their knowledge of math and statistics, but their expertise when working with content types (like us) is to provide insight on how to best capture the variability of human behavior.
You may be able to define the terms standard score, percentile, or stanine, but can you articulate the rationale behind the norming process of your favorite standardized test? Can you accurately describe the math and statistics-based validity, reliability, and evidence-based properties of your favorite non-standardized assessment tools? In any assessment tool choice you make, you are responsible for the appropriate application of that tool—to the right person, for the right reason(s), in the right place, at the right time. Our Code of Ethics requires it.
If you’ve read this far, you may be reaching for a paper sack right now to help with your breathing or needing someone to elbow you to remain upright and awake. I can’t hand you that type of support in this article, but I do have something that hopefully will be even more helpful. With the integration of the Pearson and PsychCorp businesses, we’re just beginning to enjoy all the things we can share across the Minnesota and Texas campuses. One very special document that our colleagues in Texas have created is called a “Psychometrics Primer.”
It’s a way of looking at psychometrics from an SLP’s perspective. I’d call it “required reading” for every student in the professions as well as a great reference and a helpful reference for every professional in practice today.
With all the questions we receive at Pearson from professionals who use our products, we know that we can’t say enough about what goes into putting a tool like the CELF, PLS, PPVT, or GFTA together. It’s more than numbers and pretty colors on the packaging, to be sure (although we do like how our products look). As you read, share, and ponder the attached document, please email us as you have questions about how our tools are created and how they apply to the work you do, individually and collectively.
Oh, and do keep in mind—math is a language too!