Abstract

 

Accepted 11th January, 2017

 

The deterioration of students’ performance in the Botswana General Certificate of Education (BGCSE) examination results is a disturbing trend that bothers parents, teachers, policy makers and government. This problem prompts this study on dimensionality analysis of students’ performance in 2013 BGCSE Agriculture Examination, to determine its dimensionality. The population of the study was all the 12784 students’ responses who sat for the 2013 BGCSE Agriculture examination. The students’ responses were analysed using factor analysis and IRT (1PL, 2PL and 3PL) models to examine the psychometric parameter estimates of the forty test items; dimensionality analysis and the chi square test for each test item that fitted in the three IRT models.  The findings revealed that examination was not unidimensional. None of the 40 items fit the 1PL. Only one fitted the 2PL and 8 items fitted the 3PL. In conclusion, the results of this study, as it explored the national assessment tool, showed that 2013 BGCSE Agriculture Examination was not unidimensionality. It was, therefore recommended that test developers and examination bodies should consider improving the quality of their test items by conducting IRT psychometric analysis for item validation.

Keywords: Agriculture education, unidimensionality, factor analysis, item response theory, invariance, psychometric analysis.