<p>tokenadult can probably provide the link to the CB research paper on the development of the concordance tables. I read it several years ago. However, as I recall, it was not based on anything like the full possible population of 1.4 million. The sample size was much, much smaller. There were very few students at the top end of the score range on either test. I think the concordance tables are realistic in the mid-ranges. However, in my opinion, there were too few students near the top to place much trust in the conversions in either direction. Also, near the top, individual students’ idiosyncrasies in testing can affect which test “works” better for a given student. I think that bright but sometimes sloppy students will often do better on the SAT (purely a personal opinion–based on an even smaller sample space than the concordances).</p>