Psychometric Assessment of Botswana's 2018 Junior Certificate Agriculture Science Items through Item Response Theory

Abstract

This study aimed to assess the psychometric properties of the Junior Certificate Examination (JCE) agricultural science multiple-choice items in Botswana, using the 3-parameter logistic model (3PLM). Adopting a quantitative descriptive research design, the study analyzed responses from 40,343 examinees who took the 40 multiple-choice items in the 2018 JCE agricultural science examination. The study utilized secondary data from Botswana Examination Council (BEC) records. They also obtained the ethical clearance from the Institutional Review Board of the University Cape Coast. The analysis, conducted using 3PLM within the R-studio environment revealed that 15% of items exhibited poor discrimination indices, 10% had difficulty and 12.5% were prone to guessing. There was an identification of Key anomalies in specific items, warranting careful consideration. Approximately 90% of the multiple-choice items fell within the good difficulty level range but 10% appeared to be poor difficulty. For item discrimination, up to 85% were within the acceptable range while 15% were outside. The study recommends a thorough revision or removal of items with poor parameter estimates, emphasizing continuous monitoring and collaboration between the Ministry of Basic Education and test constructors for ongoing improvement. Additionally, the study recommends stringent review of items with extreme difficulty indices to maintain a balanced assessment.