The power of teachers’ portfolios on planning physics lessons: evidence of authentic assessment

This study examined the power of teachers’ portfolios on planning physics lessons as a form of authentic assessment in public secondary schools in Moshi District Council, Tanzania. A convergent mixed-methods approach was applied using the Reflective Practice Theory (RPT). The study targeted 2830 individuals, including school heads, physics teachers, students, and District School Quality Assurance Officers. Sampling methods included simple random, stratified random, and expert sampling, yielding 363 respondents. Assessment experts ensured validity, while reliability was confirmed using Cronbach’s alpha (0.84 for teachers and 0.79 for students). Trustworthiness was established through peer debriefing and triangulation. Quantitative data were analyzed using percentages, frequencies, and mean scores, while qualitative data underwent thematic analysis. The study revealed that while teachers prepare portfolios, poor organization and limited accessibility hinder effectiveness. It was concluded that teacher portfolios are powerful assessment tools that provide evidence of students’ learning. The study recommends improving portfolio organization to better track student learning and provide constructive feedback for improved teaching outcomes.