analyzing and using test item data

Analyzing and using Test Item

Data

Item analysis techniques are among the most valuable tools classroom teachers use in improving the quality of their classroom tests. Analyzing and using test item data are focused in this chapter.

Purposes and elements of item analysis

As pointed out by Payne(1992), item analysis is conducted for the following purposes:

To select best available items for the final form of the test;

To identify structural or content defects in the terms;

To detect learning difficulties of the class as a whole; and

To identify the areas of weaknesses of students in need of remediation.

There are three main elements in an item analysis. These elements are as follows: examination of the difficulty level of the items, determination of the discriminating power of each item, and examination of the effectiveness of distracters in a multiple choice or matching items.

Index of difficulty- the difficulty level of an item

By index of difficulty is meant the percentage of students answering correctly each item in the test.

Index of discrimination- refers to the percentage of high-scoring individuals responding correctly versus the number of low-scoring individuals responding correctly to an item.

Preparin

g

Data fo

r Data

Item analysis

Preparing data for item analysis of a classroom test involves counting the number of students in high and low-scoring groups responding correctly. This can be done by asking students to raise their hands on items which they correctly answered.

There are

steps t

o

be follo

wed in

preparin

g data fo

r

item analysis

Arrange test scores fron highest to lowest. This is based on the student’s total score on the test.

Get one-third of the papers from the highest scores and the other one-third from the lowest scores. These two extreme sets of examination papers are the criterion groups. The fiest is the upper group and the latter is the lower group. The middele group is not used in the analysis of the test items.

Record separately the number of times each alternative was chosen by the students in both groups.

Add the number of correct answers to each item made by the combines upper and lower groups.

Compute the index of difficulty for each item, following the formula:

Where:IDF= index of difficultyNRC= nimber of students responding correctly to an itemTS= total number of students in the upper and lower groups

Compute the index of discrimination, based on the formula:

Where:IDN= index of discriminationCU= number of correct responses of the

upper groupCl= number of correct responses of the

lower groupNSG= number of students group

item

group AnswersA B C

D

Total no. of correct answers

Difficulty of index

H_L Discrimination index

1 H 20L 20

3 14 2 1

10 7 3 0

21 52.5 7 0.35

2 H 20L 20

0 0 18 2

0 32 9 8

27 67.5 9 0.45

3 H 20L 20

4 8 4 4

10 2 4 4

10 25.0 6 0.30

4 H 20L 20

3 3 4 10

2 4 10 4

14 35.0 6 0.30

5 H 20L 20

15 2 2 1

1 10 4 5

16 40.0 14 0.70

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