.4 Grading and Accountability


Grades are predictors of future performance not measures of achievement. That is a powerful idea because teachers really get confused thinking that they are giving grades because this is what the kid's achieved rather than giving grades because this is the predictor of future success. It's a really big, big confusion so you really have to find ways to understand how grades are used as predictors.

Let me give a good example: SAT scores which are a bane to a lot of people, SAT scores and other kinds of tests, standardized tests-what percentage of the total performance of the student do they predict? Well it turns out that the correlation statistically, and they've done a lot of statistics on this, turns out to be about 0.65. Now 0.65 is about 40% of what is going on. So if you give an SAT test and you use that as a predictor about future success, the SAT test will predict 40% of what will happen. That means that 60% of what is likely to happen, it doesn't predict. 40% it predicts, 60% it doesn't predict. Now let's take grade point averages. How much future success, do you think a grade point average would predict? What percentage of future success will grades predict if the best standardized test predicts about 40% of what's going on?
Discussion:
Student: The same
DWA: You,re right, they predict about 40%. Now here's the big question. Let's say you add together the test scores and the grades, how much do they predict together? 40% FOR the test scores alone, 40% the grades alone, put them together what would they predict? Guess? Go ahead.
Student: 50%
Student 20%

DWA: 20%! You put them together and they predict less? That would be possible. It turns out that it is not less, it's not more, it's 40%. You add in interview data, it is another 40%, you add in service kinds of things--40%. In other words, no college admissions formula has ever been able to do much better than a 40% predictor. That's the prediction. The correlation between grades and performance.



Are the best grades an accurate record of past achievement and an accurate predicter of future achievement?

 

Mr. Williams teaches an SAT preparation course at John F. Kennedy High School. Half of his class is making an A in the class and have fairly high (3.0-3.5) GPAs. The other half of his class is struggling with the class and have fair or poor GPAs. How can Mr. Williams explain and emphasize the importance of the SATs as well as grade point average without making his whole class panic?