1. Dept. of Community Medicine, PDU Government Medical College,
ITEM ANALYSIS
Dr. Umed V Patel
Associate Professor
Dept. of Community Medicine,
PDU Government Medical College,
Rajkot

2. OBJECTIVES At the end of this session the learner should be able to:
Define item analysis and to understand the purpose of item analysis
Explain the procedure for calculation of Difficulty index, Discrimination index and Distracter effectiveness.
Review MCQs and make judgment on the basis of item analysis and suggest improvements for defective items.
List uses of item analysis

3. What do you like?
Movies
Cricket
Statistics
All of the above

4. What is common theme in all four photographs
What is your analysis?

5. MCQs (Items)
Objective evaluation is becoming more important and popular in education
With greater usage of MCQs in various kind of examinations, Large no. of MCQs (Question bank) with different level of difficulty requires.
In addition, MCQs are used to assess class performance as a part of formative evaluation.
Formative evaluation: It is to determine how much and how well students have learned, to serve as a feedback to students & teachers.

6. VALIDATION It is an important step in formulation of MCQs.
Validation require at TWO stages.
Pre-validation: It is a process to which a constructed item is subjected prior to appearing in an examination.
Post validation: It is the process of analysis of the item after it has appeared in a test. (item analysis)

7. DEFINITION
Item analysis is the process of analyzing the performance of a MCQ after it has appeared in a question paper.
Statistical procedure is require to analyze a question (item)

8. Purpose of Item analysis:
Whether the item is of appropriate level of difficulty
Whether the item is capable of discriminating between the knowledgeable and less knowledgeable students.
To get the “functionality” of alternatives(options) to the corrected response
To create question bank with known difficulty and discrimination capacity.

9. Item Analysis Provides:….
Distracter Effectiveness
Discrimination Index
Difficulty Index

10. Item Analysis Provides:….
1. Difficulty Index (P)
The question difficulty is the percentage of students who selected the correct response
2. Discrimination Index (item effectiveness - d) 
Indicates how well the question separates the students who know the material well from those who don’t
3. Distracter Effectiveness – Effectiveness of the options(alternatives) given

11. PROCEDURE The essential steps of item analysis are:
1. Score the whole test for all the students.
2. Rank the students in order of merit based on their test scores.
3. Take the top third as high achievers and bottom third as low achievers.

12. Options (H) (L) Total response N(%)
4. Prepare a table for each item as follows:
Example. Item No 1 ` Key (correct response “C”)
Options
No. selecting the option amongst
high achievers
(H)
No. selecting the option amongst low achievers
(L)
Total response
N(%) A 5 10
15 (15%) B C 30
40 (40%) D
20 (20%) E
Nil 2
2 (2%)
Not responded 8 --
Total (N) 50
100

13. 5. Calculate various indices 1. Difficulty index
Indicated by the symbol ‘P’ and is calculated by the formula
P = H + L x 100 N
Where,
H = No. of students answering the item correctly in the high achieving group.
L = No. of students answering the item correctly in the low achieving group.
N = Total number of students in two groups including non-responders.
Thus, for the given example the value of ‘P’ = x 100 = 40 %
100

14. Interpretation of Difficulty Index (P)
P Value
Interpretation
50-60%
Good
30-70%
Acceptable
<30% & >70%
Requires Modification (too difficult or too easy

15. indicated by the symbol ‘d’ and is calculated by the formula
2. Discrimination index
indicated by the symbol ‘d’ and is calculated by the formula
d = H - L x 2 N
Where,
H = No. of students answering the item correctly in the high achieving group.
L = No. of students answering the item correctly in the low achieving group.
N = Total number of students in two groups including non-responders.
Thus for the given example the value of ‘d’ = x 2 = 0.4
100
Simply,
d= = = = 0.4

16. Interpretation of Discrimination Index [d]
d Value
Interpretation
≥0.35
Excellent discrimination
0.25 to 0.34
Good
0.20 to 0.24
Acceptable
<0.20
Requires Modification
._________________._____. ___._____.___________.
A negative Discrimination Index almost always indicates a wrong item/key

17. 3. Distracter effectiveness
Any of the distracters in the item, which has not
attracted even 5% of the total responded item, is said to be a “non-functional” distracter.
In the given example, option number ‘E’ is
nonfunctional having attracted only 2% of students. So, “alternative E” should be changed

18. Item Analysis – An Example

19. 1. Award of a score to each student
ROLL NO.
MARKS 1 16 13 15 2 14 8 3 21 9 4 12 20 5 11 17 6 18 7 24 19 10 22 23
ROLL NO.
MARKS 25 14 37 16 26 22 38 7 27 8 39 18 28 15 40 13 29 41 19 30 23 42 11 31 12 43 9 32 10 44 33 45 17 34 21 46 35 47 36 48 20

20. 2. Ranking in order of merit
Marks
Roll No. 25 - 13
2,40,46 24 7 12
4,11,31,33, 44 23 30 11
5,22,42 22
26, 10
9,24,32 21
3,34 9
15,17,19,43 20
16,23,48 8
14,27,29 19
8,41 38 18
12,20,39 6 17
18,45 5 16
1, 21,37,47 15
6,13,28,36 14
10,25,35

21. 3. Divide the student in 3 groups - on the basis of performance
Question th June Total Students : 48
Higher Group 24,23,22,21,21,20,20,20,19,19,18, 18, 18,17,17,16
Middle Group ,16,16,15,15,15,15,14,14,14,13,13,13,12,12,12
Lower Group 12,12,11,11,11,10,10,10,9,9,9,9,8,8,8,7
DISCARD MIDDLE GROUP
Q Frequency Table
Alternatives
Responses of Higher Group
Responses of Lower Group a 2 3 b 5 8 C
9 = H
3 = L d - 1
Not responded
Total 16

22. Calculation of Indices
Q-1
H = 9 , L = 3 N = 32
Difficulty Index (P) (expressed as %)
P = H + L X So, P = X 100 = 37.5% N
==========================================================
Discrimination Index (d) (expressed As A Decimal Fraction)
d = H - L X 2 N
So, here, d = 9 – 3 X 2 = 0.39 32

23. Distracter Effectiveness or functionality
Effectiveness of the options
Any of the distracters(alternatives) in the item which has not attracted even 5% of the total responses is said to be a nonfunctional distracter
Alternatives
Responses of Higher Group
Responses of Lower Group
Total responses a 2 3
5 (16.1%) b 5 8
13 (41.9%) C
9 = H
3 = L
12(38.7%) d - 1
1(3.2%)
Not responded
---
Total 16
31 (100%)
Alternative d have attracted <5% student. So, it is non- functional and require modification

24. Question Bank Card Subject Objective Tested Question:….
Alternatives (A)
(B)
(C)
(D)
Correct Answer :
Stem
Year
P value
Item Type & Action
d value

25. Question Bank Card angle glaucoma
Subject : Autonomic Nervous System-glaucoma
Objective Tested : Able to name drug/S contraindicated in narrow
angle glaucoma
Question No. 1 Which of the following drug is contraindicated in narrow angle glaucoma?
Alternatives
Phenylephrine
Timolol
Homatropine
Latanoprost
Correct Answer : (C)
Stem
Year
P value
Item Type & Action
d value IV
2010
38.7%
Acceptable
0.39
Excellent
Retain

26. Uses of Item analysis
To determine if item function as expected
To improve item quality
To provides data/information for helping the students to improve their learning in class room teaching
Creation of an item bank with different level of difficulty

27. But now, its your turn to bat
Thank You
But now, its your turn to bat

28. ITEM ANALYSIS – GROUP TASK
Three hundred students were administered an MCQ test containing 200 items.
The frequency distribution table of the following items showing the number of students in the upper and lower group (100 each) who selected each alternative are prepared.
Number underlined is response to correct answer.
Calculate Difficulty Index, Discrimination Index and Distracter Effectiveness of the item allotted to you.
Group
Q No
TOP GROUP
BOTTOM GROUP A B C D NR
Group 1 1 3 19 5 68 11 12 73
Group 2 2 51 23 25 14 42 8
Group 3 93 4 33 17 13 32
Group 4 60 10 24 35 29 6

29. ITEM ANALYSIS – GROUP TASK
Calculate Difficulty Index, Discrimination Index and Distracter Effectiveness of the item allotted to you…..
P = H + L x 100 (30-70% Acceptable, <30%/>70% require modification) N
d = H - L x 2 (>0.35 Excellent, <0.20 require modification) N
Group
Q No
TOP GROUP
BOTTOM GROUP A B C D NR
Group 1 1 3 19 5 68 11 12 73
Group 2 2 51 21 23 25 14 42 8
Group 3 93 4 33 17 13 32
Group 4 60 10 24 35 6 16

30. Thank You
Again