Free Essay Sample: Item Difficulty

Item difficulty is calculated by dividing the number of students who get all the questions correctly by all the students taking the test. Therefore, for the above test is equal to 2/10, resulting in an item difficulty of 0.2.

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Item discrimination

Item discrimination is calculated by dividing the difference between the upper and lower groups of students by the number of students in one group. Therefore, for the test above, the calculation is as follows:

6 – 4 = 2

2/6 = 0.3333

2/4 = 0.5

Item discrimination is equal to 0.3333 and 0.5

Importance of item difficulty and item discrimination

Item difficulty represents the percentage of students who got answers to a test correctly. It measures the percentage of the students who got the test direct (D'Sa & Visbal-Dionaldo, 2017). It is like the mean and can range up to 100 depending on the number of students and the amount of content. As the value of item difficulty increases, it means the test is difficult. When questions have different answers as alternatives, then item difficulty is the mean score for each of the answers. Item difficulty is, therefore, important to judge if the students understood the concepts in the test. It is useful to differentiate the students that understand and those who have not. If a concept is well understood and easy, everyone gets it right, and if they get if the majority get it wrong, it means it is difficult or not well understood.

Item discrimination is essential to group students according to what they understand in a test. It involves grouping students in the top and low groups (Rush et al., 2016). It is advisable to use electronic applications to come up with the item discrimination index as it does not pitch the students' groups alone during the calculation. Item discrimination is used to show the degree of test or item; therefore, a test with more content will have lower values than smaller tests. Item discrimination is not used directly, but it is analyzed depending on the test. A test with a low discrimination index shows that it has more words content, and a review should be conducted to determine why. If a test has a negative item discrimination index, then, the exam should be reviewed to identify its weak links.

Analysis of test

The test was good as it had an item difficulty index of 0.2 and an item discrimination index of 0.3333 and 0.5. An item difficulty index of over 1 means that the test is easy and should be reviewed. If the students have mastered the content completely, then the item difficulty index can be of 0.9 and above. It the test is created to distribute, the scores of students typically have an item difficulty index of about 0.5. The item discrimination index is also all right, as it is above 0 and below 1. A negative item discrimination index shows that the students are failing the test, and the minority is getting it right. There is a relationship between the item discrimination index and item difficulty index. If the item difficulty index is high, the item discrimination index will be low and vice-versa.

Questions for the assessment

Why are the students taking the assessment?

What will be the resulting information in the test?

How will the resulting information be used?

Will the assessment bring different results if tested again?

References

D'Sa, J., & Visbal-Dionaldo, M. (2017). Analysis of Multiple Choice Questions: Item Difficulty, Discrimination Index, and Distractor Efficiency. International Journal Of Nursing Education, 9(3), 109. https://doi.org/10.5958/0974-9357.2017.00079.4

Rush, B., Rankin, D., & White, B. (2016). The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value. BMC Medical Education, 16(1). https://doi.org/10.1186/s12909-016-0773-3