Testing the parallel Serbian versions of BLOT test

Bond's Logical Operations Test (BLOT) was developed for assessing the transition to formal operational thinking. The concept of formal operations originates from Piaget's theory and represents his final stage of cognitive development. The main characteristics of formal operational thinking are combinatorial thought, hypothetico-deductive thinking and a capacity for complex propositional reasoning. BLOT is a 35 item multiple-choice test which examines all of the operations which comprise the logico-mathematical structure of formal operations. The test was translated into Serbian and used in previous research. Rasch analysis showed that the Serbian version of BLOT had good measurement characteristics. This report deals with the two parallel versions of the Serbian BLOT in which were developed for the purpose of empirically testing the role of peer's interaction on the development of formal operations. For each original item two parallel items were constructed. Parallel items were developed in a way that changes were made to the items' content only while the logical structure of the original items remained the same. Wherever possible, the structure of sentences in items was also preserved and just one term was changed for another. The sample consisted of 517 secondary school students in Belgrade. Rasch measurement showed that for 19 original items both parallel items maintained their invariance, and for another 14 items one of the parallel items had similar parameters. There were just 2 items which did not remain invariant in the parallel tests. Although majority of parallel items have measurement characteristics similar to those of the original items it was important to analyse those behaving differently because of theoretical relevance of that issue and the practical consequences in trying to measure the change in operational ability following the peer interactions.