Item Analysis of the Czech Version of the WJ IV COG Battery from a Group of Romani Children

The objective of the article is to present an item analysis of selected subtests of the Czech version of the WJ IV COG battery from a group of Romani children, ages 7-11. The research sample consisted of 400 school-aged Romani children from the Czech Republic who were selected by quota sampling. A partial comparative sample for the analysis was the Czech population collected as norms of the Czech edition of (c) Propsyco (n = 936). The Woodcock-Johnson IV COG was used as a research tool. Statistical analysis was performed in Winstep software using Differential Item Functioning; differences between groups were expressed in logits and tested via the Rasch-Welch T-test. It was discovered that higher item difficulty was noted in the verbal subtests, although variability in item difficulty was found across all subtests. The analysis of individual items makes it possible to discover which tasks are most culturally influenced.