Identification of Problematic Items and Analysis of Distractors of the van Hiele Geometry Test

A suitable tool for determining the level of geometric thinking is the van Hiele Geometry Test. In our research we quantitatively evaluate the success rate in solving individual items of the van Hiele Geometry Test and identify the reasons behind the difficulty of certain test items. In addition, we focus on modeling the nominal data of the test and analyzing the distractors in the test. Test was administered to a sample of 781 9th graders in Slovakia. We modeled the nominal data of the test with a nested 4PNL model and analyzed the distractors using characteristic curves. The research results prove that the van Hiele Test items are hierarchical and reflect the basic properties of van Hiele's theory. At each level of geometric thinking, test items 7, 9, 13 were found to be the most straightforward and test items 5, 10, 14, 19 were found to be the most challenging. Test items 14 and 19, which focused on connecting logic and geometry, had the lowest success rate of correct solutions, and their characteristic curves differed from those of the other items in the test. These items are also problematic in studies conducted in other countries and are considered the most challenging test items.