Thursday, March 01, 2007
What do estate agents and the Ku Klux Klan have in common? Why do drug dealers live with their mothers? ‘Freakonomics’ by Steven Levitt and Stephen Dubner (published by Penguin) sets out to make economics more interesting by writing from the following fundamentals –
· Incentives are the cornerstone of modern life
· The conventional wisdom is often wrong
· Dramatic effects often have distant, even subtle, causes
· “Experts” use their informational advantage to serve their own agenda
· Knowing what to measure and how to measure it makes a complicated world much less so
Of most interest to teachers will be the piece on high stakes testing, which was introduced in the Chicago Public School system in 1996. To move up a grade children needed a minimum score, teachers who produced low-test results could be censured, passed over for promotion or fired.
Teachers under pressure for results told children the answers, gave them extra time, taught to test and it was suspected in some cases, filled in the answers. Using data from 1993 to 2000 Levitt and Dubner analysed over 100 million answers and looked for unusual patterns i.e., correct answers to difficult questions by poor students in classes that scored better in one year compared to the next.
They found the same six consecutive answers to harder questions from below average students where the previous answers were uncorrelated or contained blanks. They discovered cheating in 200 classrooms (5% of the total) which they felt was a conservative estimate as the algorithm only identified obvious cheating. After retesting classes, with a control group for a comparison, cheating was confirmed and over a dozen teachers were subsequently sacked.
‘Freakonomics’ has been hyped to death and is the type of geeky book that the ‘Fast Show’s’ office joker Colin Hunt would memorise, inwardly digest and bore you to death with at every available opportunity with ‘startling’ facts about esoteric subjects like sumo wrestling. It contains some interesting, amusing and quirky writing, but it won’t change your life and as the authors admit is written with the typical detachment of statisticians. Instead of finding teachers who cheat, scrap high stakes testing.
Cheating in Texas