It’s hard to imagine now, but there was a time when only freakosophy, freakology and freakerature were respectable academic disciplines. That time was long ago. OK, so how many documentarists does it take to screw in the correlations between baby names and class barriers, between Japanese sumo scandals and American financial corruption, between violent crime rates and Roe v. Wade, and between adolescent academic achievement and bribery? Answer: Well, let’s see, first, you have to understand the difference between correlation and causation…. Right, so this affable, excitable, intermittently coherent and ultimately unnecessary adaptation of “rogue economist” Steven Levitt and journalist Stephen Dubner’s 2005 nonfiction bestseller proves less revelatory than diverting — sometimes even diverting from itself. Its range of styles and default populism both have to do with being a group effort, by Seth Gordon (The King of Kong), Alex Gibney (Taxi to the Dark Side), Morgan Spurlock (Super Size Me), Eugene Jarecki (Why We Fight), and partners Heidi Ewing and Rachel Grady (Jesus Camp). Underlining the obviousness of Levitt’s “incentives matter” mantra is about as close as the film gets to a central thesis, but that doesn’t entirely preclude the hope that more discoveries may yet lurk in heaps of heretofore unexamined data!