In PISA 2022, mathematical reasoning was defined for the first time as one of the mathematical processes in addition to the three problem-solving processes assessed in earlier cycles. According to the PISA Mathematics Framework (OECD 2023, 27) “mathematical reasoning (both deductive and inductive) involves evaluating situations, selecting strategies, drawing logical conclusions, developing and describing solutions, and recognizing how those solutions can be applied”. In this presentation, we examine how expected student actions for mathematical reasoning have been operationalized in PISA mathematics items. About half of the reasoning items were new and half were used in earlier PISA cycles, where they were defined as measuring one of the three problem-solving processes. In PISA 2022, these so-called trend items were redefined as reasoning items. Therefore, we investigated if there were differences in how the new and the trend items measured reasoning. We also analysed Finnish students' performance in the reasoning items and how this performance is related to mathematics’ lessons activities in fostering reasoning. A detailed examination of the PISA 2022 framework shows that the definition of reasoning process category emphasizes drawing conclusions, justification, and critical analysis. We found that expected student actions described in the framework could be divided into three main categories: (1) argumentation (including producing justification, producing evaluation of justification, selecting justification), (2) selecting or producing the result of the reasoning (conclusion), (3) explaining the meaning. The new reasoning items developed for the PISA 2022 study emphasized argumentation, especially the production of justifications. In contrast, the trend items emphasized producing or selecting the result of reasoning. Overall, reasoning measured in PISA is implicit rather than explicit. Only in three of the trend items, students were asked to give justification. In two items, students needed to interpret the given situation and explain the meaning. The Finnish students' performance in items requiring justification was lower than in items involving selecting the result of reasoning. In addition, the performance aligned well with the proficiency levels of each trend item, but in the new items the students showed greater variation by proficiency level of the items. The Finnish students' experiences in activities that would foster reasoning in mathematics lessons were clearly fewer than the OECD average and they were not related to students’ performance in reasoning items. Based on the results, it appears that the measurement of reasoning and the activities that promote it should be further developed in the PISA study.

OECD. (2023). PISA 2022 mathematics framework. In PISA 2022 assessment and analytical framework. Paris, France: OECD Publishing. https://doi.org/10.1787/7ea9ee19-en