Gas station without pumps

2014 March 6

Guessing correction is not guessing penalty

Filed under: Uncategorized — gasstationwithoutpumps @ 06:19
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It bothers me that even the New York Times, in an otherwise excellent article repeats a common misperception:

Students were docked one-quarter point for every multiple-choice question they got wrong, requiring a time-consuming risk analysis to determine which questions to answer and which to leave blank.

via The Story Behind the SAT Overhaul – NYTimes.com.

The guessing correction on the SAT meant that you did not have to do any “time-consuming risk analysis”—if you knew nothing about a question, it did not matter whether you guessed or left the question blank—your expected value was zero either way.

Under the no-guessing-correction system, students are forced to guess, or give up 1/5th of a point for each question left blank. Thus the new system rewards gamblers and punishes people who are cautious—rewarding a character trait that should have no influence on test scores.

Under the old system, you could guess randomly on everything you didn’t know if you wanted to—it wouldn’t hurt on average.  Under the new system, you are forced to.  Forced guessing will also penalize those who aren’t aware of time running out, and are forced to “put down their pencils” before getting a chance to randomly bubble the remaining questions. It will also penalize students who would formerly skip difficult questions, then come back to the blank ones later if they had time—leaving a question blank will come with a penalty that wasn’t there before.

I suppose it is too much for me to expected innumerate reporters (even for the NY Times) to know enough probability to understand expected values, but it saddens me that the College Board, in search of higher market share, is giving up on one of the things that they previously were doing correctly.

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