I agree with @ChoatieMom that the matriculation list tells you nothing about the quality of the education at that school. And certainly it doesn’t tell you about your own child’s chances of getting into, say, Columbia to know how many students went there over the past five years. But I think it does tell you something about the composition of the student body. And if you have four or five years of recent data, you get a pretty good snapshot of the relative mix of schools that students from that BS attend. Assuming that your child isn’t some anomaly among that student body (i.e., your kid didn’t get into Choate with a 20th percentile SSAT just because you gave the school a new dorm), then it gives you some sense of the relative likelihood of attending different categories of schools. Just to take two schools for which I had data and which are on relatively opposite ends of the spectrum: at Exeter, 51% of the students attend a “top school” (defined at top 25 nat’l universities plus top 15 LACs), and 70% attend a “strong school” (top 50 nat’l plus top 25 LACs), whereas at Brooks the numbers are, respectively, 22% and 50%. In other words, an “average” student at Exeter is likely to end up at a top school, whereas an “average” student at Brooks is much more likely to end up at a strong school, but not a top school.
Anyway, I’m just a data geek and I find this stuff interesting. Everyone can draw their own (or no) conclusions from it as they wish.