This study investigated quadratic polynomial transformation model as a means of correcting teachers’ bias in assessment process. This was an ex-post-facto research design in which there was no treatment and manipulation of subjects instead it involved the collection of data from records. Cluster sampling technique was adopted to select six hundred (600) students that were made up of ten schools. The five questions raised were answered using coefficient of kurtosis, quadratic polynomial transformation model of statistical moderation, Pearson product moment correlation and one-way analysis of variance (ANOVA) statistical techniques. The results revealed the existence of bias in teachers’ assessment scores in English Language, Integrated Science and Mathematics and that, quadratic polynomial transformation model corrected these scores in the three selected subjects to a moderate level. At the same time, there were significant relationships among the corrected or moderated teachers’ scores in Integrated Science, English Language and Mathematics before and after the applicability of the quadratic polynomial transformation model. The findings justified the need for corrections of teachers’ assessment scores in order to ascertain the quality control of teachers’ assessment in Ekiti State junior secondary schools. The study recommends quadratic polynomial model as a means of correcting teachers’ assessment scores at junior secondary schools in Ekiti State and by extension in Nigerian Junior Secondary Schools and in other countries where teachers are involved in the assessment of students in order to award certificates.
Keywords: Leniency and Teacher Assessment Scores., Quadratic Polynomial Transformation, Severity
