Cand.scient. Trude Nilsen

This thesis aims to identify and explore 1) trends and characteristics of Norwegian students' physics competence and 2) factors influencing and explaining changes in this competence. Two papers address physics competence, one in upper and one in lower secondary school. an overarching framework for physics competence and previous findings from TIMSS and TIMSS Advanced informed what types of competencies to investigate in order to address the main aim. the types of competencies explored and aims of the two papers were: 1) to identify pertinent mathematical competencies in physics and how they develop over time in upper secondary schools and 2) to identify the characteristics and influence of discourse practises and attitudes on conceptual understanding in lover secondary schools. the third paper addresses the second part of the overarching aim related to influential factors and investigates School emphasis on Academic Success (SEAS) and safe schools as explanatory variables for changes in physics competence. The methodology of the studies includes, for the most part, quantitative analyses (mainly structural equation modelling with confirmatory factor analysis), but also qualitative analyses (interviews and categorization) of TIMSS data from own survey. The main findings related to physics competence indicate that the most pertinent and also declining (from 1995 to 2008) mathematical competency in physics for Norwegian students in upper secondary schools was algebra. In lower secondary school, students' increasingly high competence in astronomy may be related to positive attitudes and extensive discourse. findings related to influential factors show that SEAS explained the increased science performance in TIMSS from 2007 to 2011. Furthermore, teacher's increased perception of safety seemed to promote SEAS. The findings may inform educational policy to continue to prioritize SEAS and safe schools and the methods used in the third paper may contribute to the field of Educational Effectiveness Research (EER). Contributions to practise may include utilizing students' positive attitudes towards astronomy to teach other topics within physics and to strengthen students' algebra competency in physics. The thesis belongs to the physics education researach fiels and the field of EER and has been carried out at the Department of Teacher Training and School Research, University of Oslo.