2. ITEM ANALYSIS
Item analysis is a statistical technique
which is used for selecting and rejecting the
items of the test on the basis of their difficulty
value and discriminated power
3. OBJECTIVES OF ITEM ANALYSIS
To select appropriate items for the final draft
To obtain the information about the difficulty value(D.V) of all
the items
To provide discriminatory power (D.I) to differentiate between
capable and less capable examinees for the items
To provide modification to be made in some of the items
To prepare the final draft properly ( easy to difficult items)
4. STEPS OF ITEM ANAYSIS
Arrange the scores in descending order
Separate two sub groups of the test papers
Take 27% of the scores out of the highest scores and 27% of the
scores falling at bottom
Count the number of right answer in highest group (R.H) and
count the no of right answer in lowest group (R.L)
Count the non-response (N.R) examinees
5. Item analysis is done for obtaining:
a) Difficulty value (D.V)
b) Discriminative power (D.P)
6. DIFFICULTY VALUE (D.V)
“The difficulty value of an item is defined as the
proportion or percentage of the examinees who have
answered the item correctly”
- J.P. Guilford
7. The formula for difficulty value (D.V)
D.V = (R.H + R.L)/ (N.H + N.L)
• R.H – rightly answered in highest group
• R.L - rightly answered in lowest group
• N.H – no of examinees in highest group
• N.L - no of examinees in lowest group
8. In case non-response examinees available
means,
The formula for difficulty value (D.V)
D.V = (R.H + R.L)/ [(N.H + N.L)- N.R]
• R.H – rightly answered in highest group
• R.L - rightly answered in lowest group
• N.H – no of examinees in highest group
• N.L - no of examinees in lowest group
• N.R – no of non-response examinees
9. DISCRIMINATION INDEX (D.I)
“Index of discrimination is that ability of an item on the
basis of which the discrimination is made between
superiors and inferiors”
- Blood and Budd (1972)
10. TYPES OF DISCRIMINATION INDEX (D.I)
Zero discrimination or No discrimination
Positive discrimination
Negative discrimination
11. ZERO DISCRIMINATION OR NO
DISCRIMINATION
The item of the test is answered correctly or
know the answer by all the examinee’s
An item is not answered correctly any of the
examinee
12. POSITIVE DISCRIMINATION INDEX
An item is correctly answered by superiors and is
not answered correctly by inferiors. The
discriminative power range from +1 to -1.
13. NEGATIVE DISCRIMINATION INDEX
An item is correctly answered by inferiors and is
not answered correctly by superiors.
14. The formula for discrimination index(D.I)
D.I = (R.H - R.L)/ (N.H or N.L)
• R.H – rightly answered in highest group
• R.L - rightly answered in lowest group
• N.H – no of examinees in highest group
• N.L - no of examinees in lowest group
15. Another method for discrimination index(D.I)
If you take Likert scale for data collection
The correlation between each item scores with total
scores.
16. General guidelines for discriminating index (D.I)
According to Ebel ,
D.I Item Evaluation
≥0.40 Very good items
0.30 - 0.39 Reasonably good but subject to
improvement
0.20 – 0.29 Marginal items , need
improvement
<0.19 Poor items . Rejected or revised
17. General guidelines for difficulty value (D.V)
Low difficulty value index means, that item is high difficulty one
ex: D.V=0.20 » 20% only answered correctly for that item.
So that item is too difficult
High difficulty value index means, that item is easy one
ex: D.V=0.80 » 80% answered correctly for that item. So that
item is too easy one
19. Relationship between difficulty value and
discrimination power
Both (D.V & D.I) are complementary not contradictory to each other
Both should considered in selecting good items
If an item has negatively discriminate or zero discrimination, is to be
rejected whatever the difficulty value
20. CRITERIA FOR SELECTION AND REJECTION
ITEMS
Positive discrimination index only selected
Negative and zero discrimination index items are
rejected
High and low difficulty value items are rejected
21. REFERENCE
Sharma R.A (2007);Essential of Scientific Behavioural Research,
Meerut, Lall book depot.
Mehta D.D (2011);Educational Measurement and Evaluation,
Meerut, Tandon publication.
Kulbir Singh Sidhu (2005);New Approaches to Measurement and
Evaluation, New Delhi, Sterling Publishers.
Akbar Husain (2012);Psychological Testing, New Delhi, Pearson.
