OECD PISA methodology and the interpretation of Polish students’ results in the area of science

The article presents the results and methodology of OECD PISA – the largest and most prestigious contemporary international study on pupils’ competence. The main methodological assumptions of sample surveys and their comparison with the analysis of data from the examination system are discussed. The article presents procedures for the creation of test items, with a particular focus on the tasks in the area of science and the rules of interpretation of the test results, with particular emphasis on the principles of statistical inference. Also discussed is the importance of the effect of the incomplete sample and subsequent attempts to interpret the results.