Item Analysis

Dr. Niraj Pandit, MD

Department of Community Medicine

SBKS MIRC

Objectives of lecture

Understanding Item and why its required to study.

Tools of item analysis Method of analysis Record keeping of analysis results

Introduction

It is the analysis of Item (MCQ). It is importance to evaluate the

effectiveness of the items. This is done by studying the student’s

response to each item.

Need for IA

Item analysis information can tell us – if an item (i.e. the question) was too easy

or too difficult, – how well it discriminated between high and

low scorers on the test and – whether all of the alternatives functioned

as intended.

Advantages of IA It aids in detecting specific technical flaws and thus provides

information for improving test item. It provide useful information for class discussion of the test,

e.g. easy item can be skipped over and treated lightly, answers to difficult items can be explained in detail and items be pointed out to the students rather than defended as fair.

It provides data for helping the students to improve their learning. The frequency with which incorrect answer is chosen reveals common errors and misconception which provides a focus for remedial work.

It provides insight in skills which lead to preparation of better test in future

Tools for analysis

1.      The difficulty of the item (Difficulty Index)

2.      The discriminating power (Discrimination Index)

3.      The effectiveness of each alternative (Distracter effectiveness)

ITEM-ANALYSIS PROCEDURE

Method

1) Arrange the test papers in rank order from the highest score to the lowest score.

2) Select one third of the papers with high score and call them the Higher Group.

3) Select another one third of the papers with low scores and call them Lower Group.

4) Set aside the middle third. (This will not be used in analysis)

Prepare a FREQUENCY TABLE by counting the number of students in the Higher Group who selected each alternative. Similarly count for Lower Group also. Tabulate item wise analysis as follows:

ITEM No. ________

  

Alternatives* Number of responses.

  HigherGroup

TOTAL(H)

LowerGroup

TOTAL(L)

A        

B        

C        

D        

E        

No response        

•*Encircle the correct response for each item.

•# Total Response T = … … … … …

Sem.

Date Group SizeOf

Group

Chosen Answer Diff.Index

(P)

Discr.Index

(d)

        A #B C D NR*

   

4 20/1/2009 HIGH 30 2 20 5 3 0

    LOW 30 8 3 1 18 0    

                     

                     

                     

                     

                     

                     

Calculate item Difficulty (P) by using formula

P= (H + L) x 100/T– Where, H= no. of correct responses in higher group

L= no. of correct responses in lower group T= total no. of responders from both the

groups   NOTE: P is usually expressed as percent. The

lower the percentage figure, the more difficult is the item.

ITEM DIFFICULTY (P)

Item Poor Marginal Good Excellent P (%) 30 40 50 60   Action: (discard) (revise) (store) (store)

RECORD these values on the item bank card

Calculate the index of discrimination of the item (d) d=2 x (H - L)/T   NOTE: d is reported as a decimal

fraction. Maximum positive discriminative power is

indicated by 1.00

DISCRINATION INDEX (d)

Item Poor Marginal Good Excellent d <0.15 0.15-0.24 0.25-0.34 >0.35   Action (discard) (revise) (store) (store)

Explanation

The questions with item difficulty 50 – 60% are considered good, 30 – 70% is acceptable and those with index above 70% or below 30% require modification.

The questions with discrimination index 0.35 and above are consider excellent, 0.25 to 0.34 good, 0.20 to 0.24 acceptable and those below 0.20 require modification.

Sem.

Date Group SizeOf

Group

Chosen Answer Diff.Index

(P)

Discr.Index

(d)

        A #B C D NR*

   

4 20/1/2009 HIGH 30 2 20 5 3 0

    LOW 30 8 3 1 18 0    

                     

                     

                     

                     

                     

                     

Sem.

Date Group SizeOf

Group

Chosen Answer Diff.Index

(P)

Discr.Index

(d)

        A #B C D NR*

   

4 20/1/2009 HIGH 30 2 20 5 3 0 38 0.56

    LOW 30 8 3 1 18 0    

                     

                     

                     

                     

                     

                     

 

Smt. B. K. Shah Medical Institution and Research Center, PipariaDepartment of Community MedicineQUESTION BANK CARD (SPECIMEN)

SUBJECT National health days

Objective/s tested Awareness about national health days

   

Que. No. … … …(Stem)

World Health day is observed on

Alternatives: A. 1st DecemberB. 7th AprilC. 1st JulyD. 7th September

Reference:

Thank You

Best Luck