Interrogating the Construct of PRETCO-Oral: Longitudinal Evidence From Raters and Test-Takers.

In speaking assessment, many factors such as characteristics of test-takers, test tasks, rating bias, etc. may affect the speaking performance of test-takers. Besides, the stability of raters' rating of a speaking test might pose a threat to its reliability, validity, and fairness, which calls for longitudinal construct validation of the speaking test. This study explores the construct validity of PRETCO-Oral through analysis of data retrieved from various sources, including longitudinal ratings of performances of test-takers across four occasions, and perceptions of the construct of PRETCO-Oral from both raters and test-takers. The results indicate that raters' ratings keep stable and the PRETCO-Oral assessment is equipped with longitudinal reliability; tasks of Interpretation and Presentation represent a large amount of variance of the construct, while those of Reading Aloud and Question and Answer seem to be construct-underrepresented, as evidenced via analyzing the data collected from perceptions of raters and test-takers upon the test construct. Finally, factors that threaten the construct representation are also discussed.