Abstract:
The main purpose of this study was to analyse the psychometric properties of
the Junior Certificate Examination (JCE) agriculture multiple-choice items
using item response theory. In addition, the study examined Differential Item
Functioning (DIF) in relation to sex, location, and school type. The study
adopted the descriptive research design. Utilising the census approach,
123,218 candidates‟ responses with 4,928,720 cases of data points from the
2018-2020 examination period was used for the study. Secondary data on
candidates‟ responses to each item were obtained from Botswana Examination
Council (BEC). The 3-parameter logistic model of IRT was utilised for
purposes of data analysis. Raju‟s procedure was employed for the DIF
determination using DifR package within the R-studio environment. The study
revealed that items had varied levels of difficulty, 15% to 20% of the items
exhibited poor discrimination, and some items had high guessing indices. It
was also revealed that agriculture science items had both uniform and
nonuniform DIF across demographic variables. The study concluded that the
contribution of items to student achievement in agriculture science was good
with few items having validity and reliability concerns. It further concluded
there exists DIF across all three demographic variables of gender, location,
and school type. Resource disparities and sex-based cultural practices
contribute to most DIF items. It was recommended that BEC should consider
validating their examination items using IR.
