Quote:
Originally Posted by Ian Curtis
Perhaps I am not smart enough to understand the College Board, but it seems like if you only need to get 50% of the test right to be as good as a college student getting an A you are losing a lot of resolution you could be using to separate students.
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This is a misconception a lot of people have about testing.
If a large percentage of the population is getting 90% and multiple 100% socres, then THAT is where you are losing a lot of resolution. Saturation of data (in this case, 100% scores) means you're really not separating those at the top.
Many people believe the ideal test of subject knowledge should have the median score around 50%. Practically no one should get 100%. There should be a wide range of difficulty to the questions, from fairly easy to extremely difficult. By constructing a test this way, they hope to achieve the "characteristic of discrimination" in the test - which means the results should be able to separate the test takers along the entire spectrum of knowledge and understanding - not have everyone lumped into a tight band.