Conference with the class as a whole at the end of units to get a sense of their likes-dislikes and to give direction for planning other themes. Contracts are possible in science for students doing projects and independent work.
Portfolios are useful as an ongoing measure of student work.
They can be used at all grade levels. Use portfolios and records of conferences to validate a student's mark when reporting to parents. The portfolio provides samples of the quality of student work and their own and peers' ratings. Together with the teacher's assessment and observational notes these become a cohesive collection tracking student progress. In this assessment, either each member of the group or the group as a whole provide an assessment of their effort in the assigned task.