The SAT, the ACT, and 'Income Bias'
To answer the question, I combined a few different data sources -- this list of SAT results by income, this list of ACT results by income, and this list of ACT-SAT concordance scores. I converted the ACT scores to SAT scores and then, because the income groupings are different, I calculated the midpoint of each group and used it as the X variable. (I had to leave off the "and up" groups in both.)
Here are the results:
The ACT had much more fine-grained data at the low end, and the SAT had more data for the rich, but otherwise the two show pretty much the same thing.
Robert VerBruggen is editor of RealClearPolicy. Twitter: @RAVerBruggen