Purpose: Achievement in mathematics and reading is a function of many interrelated variables. Therefore, it is important to identify and compare the variables that affect success in these areas. The aim of this study is to examine the characteristics that are thought to be effective on achievement scores in reading and mathematics. Method: The data of this study, which is a correlational study, were obtained from the PISA 2015 Turkey sample. The analysis of the research was carried out with The Latent Regression Rasch Model, which is one of the multilevel analysis methods. Results: According to the results, female students were more successful than male students in reading and math. The student's SES and anxiety level were associated with success in both areas, and this relationship was more in mathematics than in reading. In addition, while there was no significant relationship between motivation and reading success, this relationship significantly increased mathematics achievement. Recommendations: It is recommended to carry out the necessary studies in order to reduce the exam anxiety levels of the students, and to increase the motivation of success by giving importance to the cooperation of students, parents and schools. In addition, future studies can examine the relationships between different fields (such as science, foreign language) and different variables. [This paper was published in: "EJERCongress 2022 Conference Proceedings," Ani Publishing, 2022, pp. 335-344.]