The national physics and chemistry exams and the learning of sciences

Dissertação apresentada para obtenção do Grau de Doutor em Ciências da Educação, pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa

This work has as its starting point the acknowledgement of significant fluctuations in the degree of difficulty of the Physics-Chemistry national exams. The study of these fluctuations from 1949 to 2005 aims to understand to what extent the differences, which occurred in the content, the structure of the exams, and the adopted standards, are reflected on the degree of difficulty they present. It reports and provides comparative standard-setting results of Portuguese exams of Physics and Chemistry for the nine and the last years of secondary schooling through the use of different item-grouping approaches. Three standard setting methods, Contrasting Groups, Beuk and Extended Angoff, were applied in order to study the differences in item, panellist and item difficulty in final performance. Initially, my goal in this work was to investigate the existence of possible differences in exam results in a logical and holistic manner, as to promote improvements in the teaching and learning process. I found, however, that it was very difficult to establish a single difficulty variation pattern due to the heterogeneity of the results. Even though the cognitive analysis allowed for the creation of a group of items, the evolution in the exams analysed, in a 50 year period, reflects the changes in the educational policies and allow for other considerations to be pondered based on different political, social and economic contexts.