1. A COMPARISON METHOD OF EQUATING CLASSIC AND ITEM RESPONSE THEORY (IRT): A CASE OF IRANIAN STUDY IN THE UNIVERSITY ENTRANCE EXAM 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

2. Outline  Abstract  Introduction  Methodology  Results

3. 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

4. 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

5. 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

6. 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

7. 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)

8. Methodology  Sample size  sampling error of 0.5 %  confidence level of 95 %  for form A  1054 participants  for form B  1241 participants

9. 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

10. Results Table 1: Deceptive statistics Table 2: Summary of Results

11. 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

12. 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

13. Results

14.  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