The PSLE scoring system in Singapore was changed in 2021 to move away from the traditional T-score system to a new scoring system based on Achievement Levels (ALs). Here are the key changes:

1. From T-scores to Achievement Levels (ALs): Under the old T-score system, students were ranked based on their relative performance in the cohort. In contrast, the new AL system provides an absolute measure of a student's performance, regardless of how well their peers did.

2. Four Achievement Levels: There are now four ALs instead of 29 T-score bands. AL1 corresponds to the top 2% of the student population, while AL4 corresponds to the bottom 35%.

3. Broadening of the Scoring Bands: The ALs are broader than the old T-score bands. This means that students with similar levels of achievement will be placed in the same band, reducing the emphasis on fine distinctions between students.

4. Focus on Subject Mastery: The new scoring system is designed to focus on a student's mastery of each subject, rather than just their overall performance. This means that students who do well in specific subjects will be recognized for their strengths.

5. Reduction in Exam Weightage: The PSLE is no longer the sole determinant of a student's placement in secondary school. School-based assessments and students' portfolios will be taken into account as well.

Overall, the new scoring system aims to reduce the emphasis on high-stakes examinations and instead focus on a more holistic assessment of a student's abilities and strengths.