Abstract

The study examined the differential item functioning of National Business-Technical Examinations Board (NABTEB) Agricultural Science multiple choice test items (2015-2017) in South East Zone. The study adopted Descriptive Survey research design and Ex-Post-Facto research design. Two research questions and two null hypotheses were raised and formulated respectively that guided the study. The population of the study was 10, 194 Agricultural Science students which includes 5043 males and 5151 females Agricultural Science students. Sample size of 728 Agricultural Science Senior Secondary School students (SSS III) were proportionately drawn from the 72 selected secondary schools that constituted the sample size of the study. A multi-stage sampling technigue was usedfor the study. The instrument used for data collection was NABTEB Agricultural Science constructed in 2015-2017. The instrument was re-validated by three experts, two from Measurement and Evaluation and one from the Department of Agricultural Extension Education; allfrom Michael Okpara University of Agriculture, Umudike. The data obtained was analysed using Kuder Richardson Formular 20 with reliability indices of 0.76. Data obtained for the study were analyzed using the Scheuneman modified Chi-square statistic to analyse all the research questions and chi-square test statistic was employed in testing the null hypotheses. Results showed that Agricultural science multiple-choice test items used in NABТЕВ 2015-2017, contain test items that significantly functioned differentially for testees on the basis of gender and school location. That there was no significant difference in the percentage of the number of items thatfunctioned differentially by gender in favour ofmales and those in favour of females in the 2015-2017 NABTEB Agricultural Science multiple choice test examination. It was thus recommended among others that test item writers for public examinations should be encouraged to use simple English language. This will reduce the tendency of introducing additional task into the measurement of Agricultural Science ability.