Dave Riegel: The Problem with Merit Pay - Politics on The Huffington Post: "...The use of test scores for evaluation of teachers is fraught with difficulties that should be obvious to any outside observer. First among them, you can't pick your students upon whom your salary might depend. Those in favor of merit pay often use the private sector as a comparison point, saying essentially that most people are paid by how hard they work or how many cases they win or how much they sell. And all that's true. But a salesman isn't forced to spend his time on customers who clearly don't want to buy his products. Lawyers don't typically take cases they can't win. But the logic of paying teachers based on performance is similar to saying to a car salesman, 'here are 30 adults chosen at random. Your salary depends on being able to sell all of them cars -- a standard car, at that -- regardless of their needs, desires, or ability to pay.' Or to tell a lawyer, 'you must win the next 30 cases that walk through your door, using limited resources, regardless of the merit of their suits, or the expense required to prosecute their cases.'
Teachers don't get to choose who walks in their doors, like the hapless lawyer or car salesman in the examples above. It's the luck of the draw. Teachers (good ones) certainly believe all children can learn, and want them to. But success in terms of test scores depends on many factors, mostly too obvious to mention, outside the teachers' control. Not the least among these, and perhaps less obvious to outside observers, is the support of fellow practitioners. In many cases, a child's learning requires the support of others besides just the classroom teacher. It depends on an administrator who can effectively create an climate for learning in the school. It may depend on reading specialists who can help students comprehend their textbooks. It may depend on intervention specialists who help devise strategies for learning disabled students to make more effective gains. It even depends on successful foundations provided by teachers in previous grade levels. How do merit pay advocates propose to disaggregate the work of a classroom teacher from the support staff around her? For that matter, how would art, music, physical education or special education teachers be judged under a pay for performance system? Would we need to implement standardized tests in those areas?..."
I work under a merit pay system. It does not work as intended.