Mr. Thomas M. Stephens:
After reading your column in Thursday edition of The Columbus Dispatch, I am left wondering whether you truly do not understand psychometrics or were simply being a sophist. My reasoning: No one with any understanding of the subject would claim that “around 35 percent of students’ scores are related to factors other than teaching, such as family income, student mobility, school readiness and parent involvement.” (my emphasis)
If, instead, you had written that “around 35 percent of the difference between students’ scores is related to factors other than teaching,” I would not be writing you.
Because of my uncertainty, I am in a quandary as to how to respond to you. Do I assume that you really do not understand your subject? Or do I assume that you were obfuscating the truth in order to make a claim that is false.
Let me know.