A Meta-Analysis to Gauge the Effectiveness of STEM Informal Project-Based Learning: Investigating the Potential Moderator Variables

In recent decades, informal project-based learning (PjBL) for science, technology, engineering, and mathematics (STEM) education has gained immense significance. Though some meta-analytical studies have reported the effectiveness of PjBL models, none of them has been explicit for informal PjBL models executed for school students in STEM education. Therefore, this meta-analytical study sought to investigate the effect of the informal PjBL model on students’ learning gains when compared to the traditional classroom setting. The study also intends to explore the effect of potential moderator variables that might impact the effectiveness of the model. For this, a systematic review aligning to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology has been employed, by incorporating 26 peer-reviewed empirical studies, encompassing data from 3202 students from eight countries. The meta-analytical results revealed overall moderate effectiveness ( d = 0.248, p