Kentucky's payment-by-results scheme seemed like a good idea at the time - at least to the state's education administrators. Schools where pupils showed substantial progress over a two-year period would receive between $1,845 and $3,690 per teacher.
But the plan didn't work out quite as sweetly as expected. The first problem was that the range of rewards for high-performing schools had to be reduced after it became clear that one in three schools - significantly more than predicted - had qualified for the payments. That didn't cause a major upset, however, because teachers had doubted that the money would be paid at all.
As Charles Abelmann of Harvard University told the AERA meeting, the fireworks only began to go off when teachers in the 480 successful schools were asked to allocate their share of the $26.1 million.
Some responded imaginatively. One set aside $200 for an appreciation dinner for the bus drivers; another established a scholarship fund for the classes earning the school its reward.
But in each of the four schools that Abelmann studied the division of the spoils proved time-consuming and sometimes disastrously divisive. Even in the school where the process worked best there were three staff meetings and a ballot before the teachers voted to give 15 per cent of the bonus money to ancillary staff.
Not everyone was pleased by that result. One aggrieved tea-cher posted the following staff-room notice: "To all of you who felt free to give my money away: the next time your husband gets a bonus, I hope you can convince him to give 15 per cent away to the office boy and canteen boy."
At the second school, Clarke Township High, the teachers decided that classroom assistants and secretaries should get twice as much as the canteen assistants and the janitor. Even so, everyone was relatively satisfied except the bus drivers, who got nothing.
Teachers at Sherman elementary school decided not to share any of the money with their below-stairs colleagues. One classroom assistant who had worked in the school for 22 years, said: "My feelings were hurt. It caused division in the school. Some people could not even look you in the eye."
The librarian was also dismayed: "The cooks wouldn't speak to anybody. We give this big PR speech to the community how it takes a whole village to educate children and we're all in it together, but when money comes along the teachers get it."
But the principal was even more upset: "I'm not as smart as most administrators and it took me longer to figure out how to deal with the process," he said. Eventually he phoned his old professor and asked for advice. He suggested a second ballot, which was duly organised. But the new vote, which went in favour of a wider distribution of the money, didn't help. The paltry $82 that classroom assistants eventually pocketed could never repair the damage.
At the fourth school, Truitt Falls, the principal was sharper and drew up a "shopping list" of categories that staff could allocate part of the bonus to: such as cafeteria workers, classroom assistants, playground and media centre.
But, unbeknown to the staff, the principal used his own money to "tidy up" those categories to which his staff had not wanted to donate. Face was therefore saved, but at a price.
It may come as no surprise to learn that Kentucky is now finding it harder to recruit school principals.