University of Tehran Journal of Applied Psychological Research 2251-8126 10 1 2019 05 22 Procrastination and Academic Performance: A Meta-Analysis Study Procrastination and Academic Performance: A Meta-Analysis Study 115 133 72624 10.22059/japr.2019.72624 FA Mohammad Setayeshi Azhari Journal Article 2018 10 24 Procrastination is a common problem among university and school students. To address this problem., the current research was carried out with the aim of studying the combined research effect size in the field of procrastination and academic performance. A systematic review and meta-analysis method were used in this research. Along the same lines, 30 projects through PRISMA method from web the Data (Pupmed, Springer, ProQuest, Scopus, Elsevier, Science direct, Google Scholar, Magiran), between the year 1984-2018, 1380-1396 were conducted in accordance with research objectives to perform current study. After evaluating the criteria for entrances and lay away requirements research, the correlation effects of the research were analyzed by CMA software. Also, two models of random effect and fixed effect were calculated. According to the results of heterogeneous analysis, the randomized model was selected through Q and squared I indices. The findings revealed that the size of the combined effect of the investigated research after the removal of 3 effects size was -0.307. The combined effect size of the research was calculated based on the mean Cohen’s index. The results of heterogeneous analysis revealed of the existence moderating variables in the research as well. The results of this meta- analysis pertaining to theoretical and empirical foundations are indicative of the relationship between procrastination and academic performance variables. Given the results of this meta-analysis, it can be concluded that for academic performance to be successful, it is essential to address the problem of procrastination among university and school students. Procrastination is a common problem among university and school students. To address this problem., the current research was carried out with the aim of studying the combined research effect size in the field of procrastination and academic performance. A systematic review and meta-analysis method were used in this research. Along the same lines, 30 projects through PRISMA method from web the Data (Pupmed, Springer, ProQuest, Scopus, Elsevier, Science direct, Google Scholar, Magiran), between the year 1984-2018, 1380-1396 were conducted in accordance with research objectives to perform current study. After evaluating the criteria for entrances and lay away requirements research, the correlation effects of the research were analyzed by CMA software. Also, two models of random effect and fixed effect were calculated. According to the results of heterogeneous analysis, the randomized model was selected through Q and squared I indices. The findings revealed that the size of the combined effect of the investigated research after the removal of 3 effects size was -0.307. The combined effect size of the research was calculated based on the mean Cohen’s index. The results of heterogeneous analysis revealed of the existence moderating variables in the research as well. The results of this meta- analysis pertaining to theoretical and empirical foundations are indicative of the relationship between procrastination and academic performance variables. Given the results of this meta-analysis, it can be concluded that for academic performance to be successful, it is essential to address the problem of procrastination among university and school students. https://japr.ut.ac.ir/article_72624_852a109a9c41e95d4afd7cfe8e754004.pdf