A COMPARISON METHOD OF EQUATING CLASSIC AND ITEM RESPONSE

THEORY (IRT): A CASE OF IRANIAN STUDY IN THE UNIVERSITY

ENTRANCEEXAM

Ali Moghadamzadeh , Keyvan Salehi , Ebrahim Khodaie

International Conference on Education and Educational Psychology (ICEEPSY 2011)

Procedia - Social and Behavioral Sciences 29 ( 2011 ) 1368 – 1372

Reporter : Yu Chih Lin

Outline

Abstract

Introduction

Methodology

Results

Abstract

Introduce the concept of equating

Compare classic equating and item response theory(IRT)

Advantages

Disadvantages

Different errors of equating

Using software’s BILOG and SPSS

Abstract

In the two tests

Equated with the same scale

Accuracy of equating was estimated

This study has implications for educational measurement and testing procedures

Adaptive testing

Test constructing

Introduction

Equating is a statistical method , called equating of test

Relate two or more tests

Base two or more tests on a same scale

Methods of equating general can be categorized

Horizontal

Vertical

Introduction

Determining that whether tests can be equated

Dependent on the possibility of establishing the equating conditions

Equating the tests four conditions

Similar ability

Equity

Population invariance

symmetry

Methodology

To answer the intended items, the subjects for this population were considered

People were all Iranian

Taking the test in the field of Test of language

By The Iranian measurement organization (TOLIMO)

Methodology

Sample size

sampling error of 0.5 %

confidence level of 95 %

for form A

1054 participants

for form B

1241 participants

Methodology

This test is based on three

Sub-scales of vocabulary

Structure

Listening

In this test eight questions were selected as anchor questions

According grades of the forms of A and B

Results

Table 1: Deceptive statistics

Table 2: Summary of Results

Results

Classic method has a little equating between the forms of A and B

Determining the constants, it is not needed to regard symmetry

Generally very difficult to be established in the classic method

Showed the regression indexes were influenced

Respectively the forms of A and B were the references

Results

Results showed that in the classic method

Equating is dependent to the observed sample

IRT can resolve two limits of classic method, symmetry and invariance

In IRT if the model be fitted with the data, parameters of ability can be measured

Results

In the form of A

difficulty ()

discrimination ()

In the form of B

difficulty ()

discrimination ()

Results

In addition, with IRT the parameter of ability (TETA)

Showed that the parameter of discrimination and difficulty

In different mentioned states were not significantly different