Item Difficulty in Item Analysis of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV) – Using Item Response Theory Approach (Published)
Measurement theories have gone through a lot of evolution; one of which is Item Response Theory, which is an improvement on the Classical Test Theory (CTT). This study looked into the difficulty status or difficulty parameter of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV). 512 subjects were randomly selected and administered the WPPSI-IV instrument. Findings from the study show that 241 items were good, 6 were easy, and 23 were difficult. It was therefore concluded that some items in the WPPSI-IV are adaptable and adoptable for use to measure children’s intelligence, age 7. It was recommended that WPPSI-IV is good enough and should therefore be administered to measure children’s intelligence approximately age 7. Also, it was recommended that the difficult and easy items could be replaced with better ones.
Keywords: Classical Test Theory, Intelligence, Item Response Theory, Measurement, Pupils.
Use of Differential Item Functioning (DIF) Analysis for Bias Analysis in Test Construction (Published)
The study used differential item functioning (DIF) analysis to determine item bias in a chemistry aptitude test (CAT). A total of 270 items were administered, in paper and pencil format for item analysis purposes. Items were analysed by means of classical item analysis, IRT item analysis and DIF analysis in particular. The sample size was 554 secondary school students from SS1 and SS3. The study focused on selected secondary schools in Yoruba speaking states of the western part of Nigeria, Hausa speaking states in the northern part of Nigeria and Igbo speaking states in the eastern Nigeria. The sample was divided into subgroups which was used to investigate the DIF for the level of Education, gender, language and culture. This was used to indentify items that indicated bias in terms of gender, culture, language or level of education. Items that exceeded a predetermined amount of DIF were discarded from that final item bank, irrespective of which subgroup was being advantaged or disadvantaged. The process and results of the DIF analysis were discussed.
Keywords: Classical Test Theory, Differential Item Functioning, Item Characteristic Curves, Item Response Theory