Utilisation of Rasch model for the analysis of an instrument developed by mapping items to cognitive levels of Marzano taxonomy

The scope this article was to develop an instrument to measure Chemistry students' ability regarding 'physical bonding' and to validate it. A number of 24 items were developed by mapping items to cognitive levels described by the Marzano taxonomy. A number of N=73 students were evaluated. Four items exhibited a MNSQ >1.3 and were eliminated from the final data analysis. At the final data analysis, the item difficulty measures were in normal ranges, as well as item separation and item reliability values. Person separation and person reliability values were showing that the number of items must be increased, since the instrument may not be sensitive enough to differentiate between low and high performers. Nevertheless, it was proven that the utilisation of Marzano's taxonomy in the development of items was successful in the sense that the items had difficulty measures in normal ranges and that the items had different levels of difficulty.