Collaborative and Problem Solving Instruments in Project-Based Physics Learning

This study aims to develop an assessment instrument that is able measure collaboration and problem solving abilities in project-based physics learning valid, reliable practical. type of research Research Development by adapting 7 stages development from Borg Gall. Product expert validation was carried out assess aspects construction, substance language, the results were 87.85% with very valid criteria. As for analysis field trials on 64 students using Rasch model, it obtained: (1) 21 questions about ability 19 declared valid; (2) reliability value collaborative problem-solving 0.97 0.89 (very good category); (3) average practicality test 81.21 high criteria).