Construction and validation of differential aptitude test for secondary school students in the Southwest Nigeria

Abstract

Allocation of Senior Secondary School one (SSS1) students into various subject areas (science, arts and commercial) after Junior Secondary School education in Nigeria are usually based on their performance in Junior Secondary School Certificate examinations. However, the appropriate tests needed for guidance and counselling services in determining the differential abilities of the students for appropriate allocation to subject areas is Differential Aptitude Test (DAT). This study, therefore, dealt with construction and validation of DAT for SSS1 students in Nigeria. The DAT has 62 items with six different segments which are: spelling (SP), verbal reasoning (VR), Numerical Reasoning (NR), Comprehension (CO), Mechanical Knowledge (MK), Abstract Reasoning (AR) and Spatial Ability (SA). The items in DAT have discriminating power of 0.39 and above and difficulty indices between 0.39 and 0.69. The construct validity coefficient of DAT ranges from 0.77 to 0.83 and the reliability coefficients were between 0.50 and 0.79 while the overall reliability of the DAT was 0.74. The findings of the study showed that DAT is valid and reliable to measure the differential abilities of Senior Secondary School students. It was, therefore, recommended that DAT should be used by school guidance counsellor for allocating senior secondary school students to subject combinations since it would show clearly different areas of abilities that related to their career potentialities.