Impact of Science Project-Based Assessment on Achievement and Critical Thinking of Secondary Students in Anambra State

This study examined the impact of project-based assessment on the science achievement and critical thinking of senior secondary students in Anambra State, Nigeria. Project-based assessment, which evaluates students through extended, real-world oriented investigative tasks, represents a departure from the dominant pen-and-paper examination culture and is theorised to develop deeper disciplinary understanding and thinking skills. A quasi-experimental pretest-posttest design with matched control groups was used. Students from eight SS2 classes across Awka South, Idemili North, and Ekwusigo Local Government Areas participated, with four classes assessed using project tasks integrated into their Biology and Chemistry programmes and four classes continuing with conventional assessment over one academic term. A Science Achievement Test and a Watson-Glaser Critical Thinking Appraisal adapted for Nigerian secondary students were administered, both with reliability coefficients above 0.82. Analysis of Covariance was applied. Findings showed that students in the project-based assessment condition achieved significantly higher scores on both the science achievement and critical thinking measures. The effect size for critical thinking was large, indicating substantial practical significance. Recommendations included revising the Nigerian secondary school assessment policy to formalise a project-based assessment component in science subjects, and providing teacher training in project design and rubric-based evaluation. Keywords: project-based assessment, science achievement, critical thinking, Anambra State, secondary education.