Item Analysis Presentation of Quarterly Examination

How to do item analysis

1. Item Analysis

2. Difficulty Value

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.1) 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. 。 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)
* RH —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. 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.

9. DISCRIMINATION INDEX (D.l)

“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. + 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)

・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

20.40 i Very good items

0.30 - 0.39 | Reasonably good but subject to
improvement

0.20 — 0.29 Marginal items , need
improvement

Poor items . Rejected or revised

17. General guidelines for difficulty value (D.V)

OL ow 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

OHigh 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

18. Difficulty Value

D.V Item Evaluation
0.20 - 0.30 Most difficult
0.30 - 0.40 Difficult
0.40 — 0.60 Moderate difficult
0.60 -0.70 | Easy
0.70 — 0.80 Most easy

19. Relationship between difficulty value and
discrimination power

“Both (D.V & D.D are complementary not contradictory to each other
+ Both should considered in selecting good items

#1f 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

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