Last week, I showed that the Core Index was more generous to High schools than the API had been. Here is another way to look at it.
Below is a regression of the data, showing the trend line. The trend line is predictive – it attempts to predict the Core Index score from the API. If a school’s dot is above the line, it outperforms the prediction, below would be underperform. The R-squared is only .44, so it isn’t very strong, but you immediately notice something: High Schools consistently outperformed while elementary schools underperformed.
This is not to say that high schools are doing any better, or that elementary schools are doing any worse. Instead, this is suggesting that the new measurement is much more generous to high schools, and much harsher on elementary schools.
Elementary schools will score comparatively lower scores, and may be in for a shock when they see their own data. They’re going to be having one of those “but wait, we were doing so well…are we doing worse?” moments. But the reality is that they are not doing worse – they are just being measured differently (which is never a satisfying answer).
Meanwhile, high schools are going to be having the opposite moment – they may think “We’re doing great – we’re better than we used to be”. But again, they are simply being measured differently, and it is not necessarily progress.