My PhD project is a part of approved broader project of our research group titled “multilevel modeling of single-subject experimental data: Handling data and design complexities”. As part of this project I worked on reviewing the single-subject experimental design meta-analyses published in 1985-2015 for different characteristics such as study design, kind of data, kind of analyses, methodological quality, and weighting strategy. Now I am working in simulation study for Level 1-variance components estimation in meta-analyzing the single-subject experimental designs. Afterwards, I will work on combining the results of 2 real datasets in programs for toddlers with autism (meta-analysis of group comparison designs and single-subject experimental designs).