Effectiveness of the Implementation of Project-Based Assessment in the Chemistry Teaching towards Critical Thinking Abilities and Chemistry Learning Mastery of High School Students in Sleman

This study aims at determining the effectiveness of the implementation of project-based assessment in the chemistry teaching in high schools (SMA) in Sleman in the terms of student achievements when the chemistry prior knowledge was statistically controlled, SMA students’ learning mastery in Sleman in which the teachings implement the project-based assessment, and profiles of SMA students' critical thinking skills in Sleman in which the teachings use the project-based assessment. Subjects of the study were students of class XI-IPA of SMA N 1 Sleman and ones of SMA N 1 Kalasan. The objects of the study included students’ learning achievements, learning mastery, and critical thinking abilities. The treatment instrument was in the form of lesson plans consisting of giving project works with the project-based assessment. Instruments that served as the data collection were assessment sheets of critical thinking skills and chemistry learning achievement tests. The data were analyzed using the one-point covariance test (Anakova A) and percentages of descriptive analysis. Based on research results, the conclusion was that the implementation of project-based assessment in the chemistry teaching at SMA N 1 Sleman was effective in improving students’ learning achievement when chemistry prior knowledge was statistically controlled. At SMA N 1 Kalasan, the implementation of project-based assessment has not been effective in improving students’ learning achievement. Meanwhile, the students’ learning mastery at SMA N 1 Sleman joining the teaching with the implementation of project-based assessment was achieved by 48.27% of the students while at SMA N 1 Kalasan, it was achieved by 90.62% of the students. Profiles of students' critical thinking abilities at SMA N 1 Sleman were 44.83% (good), 41.38% (medium), and 13.79% (less) while at SMA N 1 Kalasan, the profiles were 56.25% (very good), 37.5% (good), and 6.25% (medium)