LaunchPad > Explaining Difficulty and Discrimination

Document created by Digital Support on Jan 25, 2017Last modified by Digital Support on Aug 29, 2017
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Click assignment title

In your gradebook, click an assignment title to view Difficulty and Discrimination for that assignment.

Click "Difficulty" header

Scroll down to the Questions section in the main panel. Click on the Difficulty header to sort questions by difficulty percentage.


View how many students answered correctly

As you hover your mouse over one of the red and green Difficulty bars for each question, you'll see the number of students who've answered the question, and the percentage of students who got it right and wrong. Green represents correct, and red represents incorrect.


View portion of students who selected each answer choice

You can also click on the + symbol to the left of the question number to see the percentage of students who selected each answer option. Click in the same place again to collapse this view.


Click "Discrimination" header

Click on the Discrimination header to sort by discrimination. Discrimination is calculated as the correlation between how well the students answered the question and how well the students did on the assessment. Hovering over one of the bars displays a correlation score.


Meaning of discrimination score

The discrimination score that instructors desire is .2 or above. The closer it gets to 1 the better the question correlates to the whole assignment. This analysis is called "discrimination analysis" and it is a scientific method for indicating student performance on a particular item as compared to student performance on the assessment as a whole. A low positive or zero correlation may mean that this is a basic question, one that you expect all students to correctly answer. A negative correlation or low correlation is undesirable because it means performance on the question was not consistent with performance on the assessment as a whole.

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