The purpose of this quantitative, causal-comparative research study was to determine if and to what extent there were differences in chemistry end-of-course (EOC) examination scores between high school chemistry students taught using POGIL pedagogy and non-POGIL pedagogy in the state of Utah. Piaget's cognitive development theory and Johnstone's cognitive load theory served as the theoretical foundations. A large, public school district in the state of Utah provided the deidentified, archival data for this study, which consisted of students that took a chemistry course and chemistry EOC examination in 2015-2016 or 2016-2017. The research question sought to find whether there was a statistically significant difference in chemistry EOC examination scores for high school students in both groups. A one-way ANOVA demonstrated a statistically significant difference between the POGIL and non-POGIL student groups on the dependent variable of chemistry EOC examination scores, F(1, 314) = 29.91, p < 0.001, partial [eta][superscript 2] = 0.087, (p < 0.05). This study supported POGIL pedagogy as an effective instructional strategy for improving student chemistry EOC examination scores.