Viability of construct validity of the speaking modules of international language examinations (IELTS vs. TOEFL iBT): evidence from Iranian test-takers

Abstract

The aim of the present research is to examine the viability of the construct validity of the speaking modules of two internationally recognized language proficiency examinations, namely IELTS and TOEFL iBT. High-stake standardized tests play a crucial and decisive role in determining the future academic life of many people. Overall obtained scores of candidates are believed to reflect their general proficiency level. Appropriate interpretation and use of test scores depend on the extent to which items measuring a particular skill (here speaking) can meet the criteria to examine the intended construct. Speaking, amongst the other four skills, has a central place in assessing general proficiency of the candidates. This research seeks to scrutinize how IELTS and TOEFL iBT tap on the speaking proficiency of their candidates. Moreover, this study investigates whether obtained speaking scores of candidates in these two international high-stake tests show an acceptable degree of consistency in measuring the skill being examined. The chosen sample of the study consisted of 60 students who successfully completed TOEFL iBT and IELTS preparation courses in Tehran. The results of the statistical analysis show that there is a meaningful discrepancy between the two exams in assessing the speaking abilities of the exam-takers and therefore challenge the construct validity of the exams in question. Findings are then used to discuss the repercussions for language proficiency measurement and assessment.