Ratings of internalizing (e.g., anxiety, depression) and externalizing (e.g., aggression, inattention) behaviors among school-aged children have increased in recent years, negatively affecting academic and behavioral/social outcomes. Although school-based interventions are available, few are integrated within core instructional practices. Project Based Learning (PBL), a student-centered instructional approach, has demonstrated academic benefits and may also support behavioral outcomes; however, its effects on internalizing and externalizing behaviors have not been systematically synthesized. This study presents a meta-analysis examined the effects of PBL (delivered at the classroom level) has on these behavioral outcomes (e.g., internalizing and externalizing behaviors) in K-12 students. A total of 28 studies published between 2006 and 2024 met inclusion criteria, yielding 49 effect sizes. Separate random-effects meta-analyses using Correlated and Hierarchical Effects working model of robust variance estimation were fit for internalizing and externalizing behaviors, with moderator analyses exploring differences by age group and behavior domain. Results indicated a significant, moderate to large overall effect of PBL on student behavior with significant positive effects for both internalizing and externalizing behaviors. These effects did not significantly differ from one another, indicating the effect of PBL was relatively stable across all behavior types (i.e., internalizing and externalizing). Subgroup analyses showed significant positive effects of PBL for internalizing domains of motivation and self-efficacy, while effects of PBL on engagement were large but not statistically significant. Moderator analyses revealed no significant differences in effects by behavior type, age group, or subject area; though, substantial heterogeneity was observed both between and within studies, indicating further moderator analyses are indicated. Evidence of potential publication bias was detected, with smaller studies showing larger effects. Limited reporting of maladaptive behaviors and demographic variables restricted additional analyses. While results were relatively stable across age groups and subjects, the findings suggest that PBL serves as an effective proactive Tier 1 intervention that fosters prosocial development by aligning with students' developmental needs for autonomy. The study highlights the potential for PBL to shift classroom management from reactive discipline to a growth-oriented pedagogy, though further research is needed to address gaps in demographic data and rater bias.
Kiera Walker (Fri,) studied this question.