<![CDATA[Collaborative Problem Solving (CPS) is one of the essential skills of the 21st century. This skill is also must be instilled in students in learning process. CPS can be gauged by using an instrument in the form of inventory. In this study, a web-based Collaborative Problem Solving Inventory (CPSI) was developed with the Learning Development Cycle (LDC) development method. The CPSI developed by the authors is a measurement of innovative Collaborative Problem Solving, emphasizing on measurements before, during and after Collaborative Problem Solving learning activities are carried out. The stages of this research include: (1) Observation, Survey and Needs Analysis; (2) Focus Group Discussion; (3) Preparation of CPSI Design; (4) Development of Web-Based CPSI through LDC Development Model; (5) CPSI validation by experts in developing teaching materials (feasibility) and teachers (practical); and (6) Data Analysis. Based on the results of the study, it was obtained that the CPSI instrument was web-based with indicators for assessing collaboration skills that had been validated by experts and practitioners. The validation results showed that the instrument is feasible to use with minor improvements (validity 3.75 by media experts; validity 3.78 by evaluation experts; and mean 3.65 by practitioners). Follow-up research can be done by testing the instrument in a classroom learning situation, by first making improvements related to the attractiveness of the appearance and website design.]]>
