The post is complete with math and graphs that explain the two different methods for calculating quick scores and the possible grade inflation that resulted this year when the TN Department of Education switched to the cubed root method.
Here’s an excerpt that explains the point difference that would be expected based on the different methods for calculation:
The cube root method yielded on average a quick score, the score that goes for a grade, of 4.46 points higher. In other words, a student scoring basic with a raw score of 30 or higher would, on average, receive an extra 4.46% on their final quick score grade, which goes on their report card. A student who scored a 70 last year could expect to receive a 74 under the new quick score calculation.
The additional points do drop as one goes up the raw score scale, however. For the average basic student grades 3-8 with a raw score between 30 and 47, they would receive an extra 5.41 extra points under the new method.
The average proficient student grades 3-8 with a raw score between 48 and 60 would get 4.32 extra points under the new method.
The average advanced student grades 3-8 with a raw score of between 61 and 67 would receive an extra 1.97 extra points under the new method.
The difference varies much more widely for below basic students, but the difference can be as much as 25 points in some cases.
In short, final grades in subjects required to factor in TCAP scores were higher this year than they have been in the past. In some cases, these “extra points” would have moved a student up a full letter grade.
Commissioner McQueen has indicated that this method will be used going forward as the state transitions to the TNReady test, starting next year. Of course, that test is entirely different from TCAP, so comparisons between the two are of limited value — at least until there are multiple years of TNReady data to use for comparative analysis.
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