MINJUNG KIM (UNIVERSITY OF KANSAS)

COMPARABILITY OF GST AND OPIC EXAMS IN SOUTH KOREA: EVALUATING LINEAR AND EQUIPERCENTILE EQUATING METHODS : LANGUAGE ASSESSMENT AND EVALUATION

This study investigates the comparability of the Global Speaking Test (GST) and the Oral Proficiency Interview-computer (OPIc) exams in South Korea, focusing on the effectiveness of two equating methods—Linear equating and Equipercentile equating—compared to no equating. A sample of 200 students who have taken both exams is analyzed to determine the reliability, correlation, and error introduced by each equating method. The results indicate that both Linear and Equipercentile equating improve score comparability, with Equipercentile equating showing higher reliability (Cronbach's alpha) and correlation (Pearson correlation coefficient). The standard error of equating (SEE) analysis reveals that Equipercentile equating introduces less error than Linear equating. Practical effects are assessed by examining the distribution and interpretability of equated scores, demonstrating that Equipercentile equating provides more consistent and interpretable results. These findings support the use of Equipercentile equating for aligning GST scores with OPIc levels, resulting in a validated score comparison table that enhances the accuracy and practicality of language proficiency assessments. The study concludes with a detailed justification of the chosen equating methods, emphasizing their empirical basis and potential applications in educational contexts. This research provides valuable insights for educators and policymakers, facilitating more effective and reliable language proficiency assessments in South Korea.

Name: Minjung Kimm Title: Researcher Affiliation: ITSC GTELP Korea Bio: Minjung Kim is a researcher at ITSC GTELP Korea, specializing in language proficiency assessment, psychometrics, and educational measurement. She has extensive experience in statistical analysis and improving language testing methods in the field.