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This study investigated if items are bias in Edo State Basic Education Certificate Examination (BECE) 2012 and 2013 multiple choice in Mathematics test using Item Response Theory analytical procedure in relation to Socio-Economic Status (High/Low SES). Four research questions were raised, out of which, two were hypothesized and tested. The research design employed in this study was a survey research design. The instruments used to collect data for the study were a 60-item multiple choice Mathematics test items (Edo State BECE Mathematics examination papers, 2012 and 2013), and a socio-economic survey questionnaire. To detect the socio-economic status biased test items; the study used 3-Parameter Logistic Model of Item Response Theory (IRT) statistical analysis to generate the Item Characteristic Curves (ICCs) for the subgroups. The hypotheses were tested using Chi-square statistics at 0.05 alpha level of significance. The findings showed that the 2012 and 2013 Edo State BECE multiple choice Mathematics test items functioned differentially in terms socio-economic status, in favour of high socio-economic status students. Based on the findings, it was recommended among others that test experts and developers should explore the use of Differential Item Functioning approach, particularly Item Characteristics Curve method to detect socio-economic status biased items.