Can we include students who are missing SAT scores in our admission validity study?

Note that the starting point for constructing your sample for an ACES admission validity study should not be your SAT takers, it should be your entering class or the particular student sample (e.g., students admitted to your engineering school) you are focusing on for your study. Sometimes students have SAT scores on record at the College Board that the institution doesn't  have, and the SAT scores in the ACES study are taken from the College Board database. Note that it's not possible to use concorded SAT scores in an ACES admission validity study, only official SAT scores.