Examination of postgraduate theses published in Turkey about the concept of number preschool mathematics education

This study was conducted to make general conclusions about the graduate theses by analyzing the master's and doctoral dissertations written about the concept of number used in preschool mathematics education in Turkey in terms of certain variables (level, year, university, purpose, research design and approach, participant, data collection tool, data analysis method, similarities or differences between theses written for similar purposes). The study was conducted using qualitative data research methodology and a systematic literature review design was preferred. Document analysis method was used as the data analysis method. In order to determine the graduate theses to be included in the study, the YÖK National Thesis Center database was searched using keywords such as 'numbers', 'number concept', 'number sense', 'preschool', 'early childhood', 'mathematics'. As a result of the screening, studies that met the criteria were included in the research and 32 postgraduate theses, 29 master's theses and 3 doctoral theses were analyzed. Graduate theses on the concept of number used in preschool mathematics education were mostly written between 2016-2020 at Gazi University. While the study group of the theses mostly consisted of preschool children, the age distribution of the study group was 60-72 months. It was concluded that the 31-100 participant range was mostly preferred in the sample group size in the studies. While quantitative research method was mostly used in the theses examined, quasi-experimental design was preferred as the research design. Diagnostic tests were mostly used as data collection tools. The most preferred data analysis methods in postgraduate theses were t-test and non-parametric tests. When the theses are analyzed in terms of their aims, it is seen that most of the studies were conducted on the effect of method-techniques on the concept of number. Among the theses included in the study, it was seen that there were 12 theses written for similar purposes. The years of these theses with similar purposes differ from each other. In terms of the findings of the analyzed postgraduate theses, it was observed that studies on developing or implementing different methods-techniques and different mathematics programs were emphasized. In the postgraduate theses examined within the scope of the research, it was concluded that mostly positive results were obtained regarding the variable of different methods and techniques, while no significant difference was found regarding the gender variable. In the recommendations for practice of the postgraduate theses examined, it was revealed that training/seminars should be given to educators, and in the recommendations for the researcher, it was revealed that new research could be organized by making arrangements regarding the number/level of the sample.