Statistical Analysis: Yer doin' it Wrong!
The study on the determinants of college graduation rates is making a big splash. However, its analysis is, with all due respect, crap. Correlation is not causation, there are generally multiple explanations for a correlation and it is not correct to simply pick one and assert its truthfulness.
Consider this part of the story:
Students shouldn't settle for less in a college: Thousands of bright, qualified students apply only to lower-ranked schools where their grades and tests scores are above those of the average student. But the new study finds that those who attend such "safety" schools are far more likely to drop out than those who get into "reach" schools. "It is counterintuitive," Bowen says. "You might think that if Sally goes to a school where she is top dog, she will have a much easier time graduating. But that's not true. She has a better chance of graduating if she goes to school with other people as talented she is."
Well, his (Bowen is one of the authors of the study) interpretation of the correlation certainly is counter-intuitive. It is also almost certainly incorrect! How about this instead: Students who pick an easy school when higher quality options are available to them are not very interested in higher education and are signaling by their very choice that they are unlikely to complete a degree. The last sentence in the quote above should read: "She has a much better chance of graduating if she WANTS to go to a school with other people as talented as she is".
In other words, a lack of desire to get a college degree is driving both the choice of an easy school and the failure to graduate.
I am not saying that my interpretation is 100% correct, but it least it posits a causal mechanism that makes the correlation un-puzzling. The authors, to me are being almost willfully dense. They admit their view is "counter-intuitive" but can't bring themselves to think about anything else.
The next paragraph in the story makes the same mistake again:
Admissions tests don't predict graduation: SAT and ACT test scores are no help in predicting who will graduate from many, if not most, colleges. The widely used tests do help identify those likely to succeed at elite schools, the study found. But for many less selective colleges, students with higher scores were actually more likely to drop out.
Again, it's counter-intuitive unless you consider that highly qualified people picking an easy alternative are showing their actual lack of interest in the endeavor and thus are intrinsically less likely to complete said endeavor.
Putting students who don't want to go to a competitive college into a competitive college is NOT going to raise graduation rates in any significant way. Putting them into one or two year (instead of 4 year) certificate/professional training / apprenticeship programs or just getting off their backs and letting them go to work is a better way to make them happy and improve the economic health of the polity.