Inside the Mathematical Equation That Will Grade and Pay Teachers

Advanced calculus high school teacher, Orlando Sarduy, writes out the formula that will be used to grade and pay teachers like him.
MIAMI (2012-2-16) -

School has always been about grading students. But now 24 states in the country are starting to grade teachers.

Florida is using a mathematical formula to calculate how well teachers are doing their jobs. The grade it spits out will determine how much a teacher gets paid and whether that teacher can keep his or her job. But the formula is so complex teachers don’t understand how it works.

Orlando Sarduy, a college math major, teaches advanced calculus at Coral Reef High School in Miami-Dade County. Just reading the formula is difficult for him.

“I would really challenge any sort of decision maker to look at [the formula] and explain it,” Sarduy said. “I understand the just the basics, but this is really the technical nitty-gritty of what’s going on, and to me it looks the same as it would to a lay person, like ‘what's going on here?”

How The Formula Works

The formula is designed to predict how students will score on the state's standardized exam—the FCAT. And then it pays teachers if their students hit that predicted score, or not.

The formula takes into account school and student characteristics that Florida says has predictive value over how well a student is going to do in school.

Florida decided that there are only 10 factors that matter. They chose things like the number of students in a classroom, whether English is a student’s first language, attendance rates or disability status.

The statisticians created a formula that gives each of the 10 factors a certain weight in the formula.

That’s how the statisticians and policymakers who created the formula explained it to Miami Herald education writer Laura Isensee.

For example: If a student misses 5 days of school, the statisticians determine what the effect of missing 5 days of school will have on that student’s standardized test score.

The statisticians do this for each factor and every student. In the end it predicts what a student’s test score should be given all their factors.

“And that prediction will be the grading stick for the teacher,” Isensee said. “If the student gets higher than the predicted score, the state thinks, ‘they must've had good teacher.’ If a student scores below the predicted score, then the teacher could be in trouble.”

The state has a list of all the different weights for all the factors.

But Isensee said, “The weights are all over the place, even for kids who seem to be in the same situation.”

So if the factor for a sixth grader in reading class is that he's an English language learner, that affects their predicted test score with a weight of -7.3, but the weight is +12.9 for a tenth grader in reading class who is also an English language learner.

“I tried to understand why the impact is so different for everyone and the statisticians basically told me, ‘don't worry about it, that's the formula's job. The formula knows how much weight to give everything.’”

Isensee says the formula requires a lot of trust.

“The teachers have to trust that the policy makers chose the right factors, and the policymakers have to trust that the statisticians came up with an accurate formula."

Kathy Hebda is with the Florida Department of Education. She says the formula Florida created is a state of the art model.

“We’re very confident in the process and the approach we’ve taken," Hebda said. "We have contracted with leading national experts... we have a statewide committee that is steering the process and making recommendations to the commissioner about the model, that’s made up primarily of teacher. That kind of input and guidance is extremely important to make sure that the model works properly.”

Teachers like Sarduy are skeptical. He questions why Florida only chose 10 factors to begin with. There could be hundreds of factors that impact how well a student does in school, he said.

“[The formula is] only as good as the variables that you’re actually looking out for … as well as the test that you’re using to measure. At the backbone of this is still an exam that’s made up.”

The most influential factor in the equation is the score a student gets on the FCAT. Its the factor with the most predictive value.

What Happens If You Don’t Teach an FCAT Subject?

In Florida about 60% of teachers do not teach an FCAT subject, like physical education teachers, health and history teachers, or chemistry and advanced calculus teachers. There is no FCAT test for those subjects.

Insensee said that until the state comes up with a test for every subject in every grade teachers who don't teach an FCAT subject are going to be graded on the whole school's reading score.

“So heath teachers, advanced calculus teachers, their pay will be based on how well kids read,” said Isensee. That has teachers like Sarduy pretty frustrated.

"It's infuriating,” said Sarduy. “I have nothing to do with whatever that end result is."

But the state does give teachers another chance to show off their teaching skills. Hebda said the grade the formula gives teachers is only half of the whole teacher evaluation process.

“The law is very clear that that’s 50% of an evaluation. The other piece of that is equally important, which is instructional practice," Hebda said. "What is the teacher actively doing in the class? What are the students actively doing in the class? And then what are the student outcomes? Those are the things that all go into making that final evaluation result."

So principals and other educators will still do their own evaluation of teachers by sitting in their classroom and reviewing lesson plans.

But some teachers still feel like too much of the end result is out of their control.

The State Says Poverty Doesn’t Matter

Study after study we hear that poverty is the number one indicator of how well students do in school. But Florida policymakers made it against the law to include any socioeconomic status as a factor in the formula.

There’s no factor for poverty, homelessness, immigration status, race or ethnicity.

The state says the formula doesn’t need to include a student's socioeconomic status as its own factor in the formula because its already baked into the equation. Teachers would only be graded on how well they help poor students improve from the year before when they were also poor.

The rationale is that all kids, regardless of whether they're homeless or poor, can improve at the same rate as kids from wealthy areas, if they have a good teacher.

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