A Comparison of Score Equating Conducted Using Haebara and Stocking Lord Method for Polytomous

• Main Author: Risky Setiawan*
• Format: Article
• Language: English
• Published: RU Publications 2019-10-01
• Series: European Journal of Educational Research
• Subjects: Equating; polytomous; graded data.
• Online Access: http://eu-jer.com/EU-JER_8_4_1071.pdf

The purposes of this research are: 1) to compare two equalizing tests conducted with Hebara and Stocking Lord method; 2) to describe the characteristics of each equalizing test method using windows’ IRTEQ program. This research employs a participatory approach as the data are collected through questionnaires based on the National Examination Administration of 2018. The samples are classified into group A and group B respectively by 449 and 502 respondents. This paper discusses how to equalize shared items using the anchor method with a set of instruments in the forms of 35 questionnaire items and 6 shared items. In addition, the researcher also uses PARSCALE to estimate each respondent’s skills and each item’s characteristics. The shared items are eventually equalized using IRTEQ program. The results show that there is a significant difference between those conducted using Haebara method (0.592) which produces bigger mean-sigma value and Stocking & Lord (0.00213). Thus, the results show that the shared testing items may improve respondents’ discrimination and increase the difficulty level (parameter b). Due to the availability of shared items, it is good and appropriate to equalize two different tests on different theta skills.