Applying Classical Test Theory to Test Critical Period Hypothesis: The Case of Iranian EFL Learners' Grammatical Performance in a Subject-Verb Test on Agreement

The current paper pursues two aims: to employ Classical Test Theory (CTT) to develop and refine a test, and to determine the impact of the age factor on L۲ grammar among Iranian EFL learners, providing evidence for the claim that CTT best evaluates the consistency of measurements in age-related studies. The study examines the performance of adults or teenagers as pre- and post-puberty learners, in the grammar test devised through CTT, to conclude whether younger learners or older ones perform better on subject-verb agreement. Based on random sampling, twenty-three male participants, including ۱۲ adults and ۱۱ adolescents, upper-intermediate native speakers of Persian, took part in the study. They were tested on a ۶۰-item test of grammar (on subject-verb agreement), which has been developed using the CTT model, as it fits small sample sizes and can be used for understanding complex issues (e.g., age-related issues). Other than devising a test on agreement using CTT as a model, the results revealed that post-puberty learners scored better than their younger counterparts, partly because they are cognitively more mature. However, age is not the one and only factor in second language learning, and other factors like individual differences, contextual factors, and methodological rigor should be taken into account. Future work on more CTT-based assessments and developing more tests through adopting longitudinal designs can better shed light on the role of the important factors on grammatical performance, informed by the impact of the age factor.

کلیدواژه ها:

Designing Test ، EFL ، Pre- and Post-puberty ، Subject-Verb Agreement ، Tense Agreement