Project-based learning and critical thinking in car audio video installation: a quasi-experimental study

Abstract

This study examined changes in critical thinking assessment scores during Project-Based Learning (PjBL) activities involving car audio video installation in vocational education. A quasi-experimental design with a nonequivalent control group involved 30 Grade XI students, 15 in each instructional group, over two meetings within one month. The experimental group completed installation projects, while the control group received conventional instruction. Assessment comprised 15 multiple choice questions and 10 essay questions covering technical knowledge and reasoning. Across the combined sample, mean scores increased from 60.10 at pretest to 82.97 at posttest, and standard deviation decreased from 10.246 to 4.672. The mean normalized gain was 0.563, indicating moderate improvement. These descriptive findings show higher overall performance following instruction, but do not establish a difference in effectiveness between PjBL and conventional teaching because results were not reported separately for the two groups. The study illustrates how project activities can integrate technical decision making, analysis, and reflection, while highlighting the need for group comparisons and documented instrument quality.