We've been writing a lot about the various often subtle and unanticipated ways that selection effects can affect educational metrics. I don't think we ever considered the possibility of schools paying the students at the bottom of their classes not to take certain tests.
From Paul Campos:
Bar-passage rates at the InfiLaw schools are now in a free fall. (The following percentages are for first-time takers of the July exam in the schools’ home states.) Florida Coastal’s bar-passage rate has fallen from 76 percent to 59 percent, Charlotte’s has fallen from 78 percent to 47 percent, and Arizona Summit’s has gone from 75 percent to an astonishing 30.6 percent.This collapse has taken place despite the fact that, according to allegations in a lawsuit filed by a former Arizona Summit administrator, all three schools have been offering money to graduates who the schools identified as being at especially high risk for failure, to get them to hold off on taking the bar exam. Indeed, in July Arizona Summit’s dean confirmed that she had called various graduates the night before the exam, imploring them to consider the “opportunity” to withdraw from the test, in exchange for a $10,000 living stipend, that would be paid to them if they enrolled in enhanced bar-preparation courses provided by the school.