The Program in Education, Afterschool and Resiliency (PEAR) at Mclean Hospital and Harvard University, has been implementing NSF supported ILSA project. During the multi-year study, we realized that there is no comprehensive assessment tool for Out-of-School Time science program. Therefore, we at PEAR created “Dimensions of Success- (DOS)”, an observation tool for informal science learning. Building upon the Friedman-Ucko framework, the DOS tool has 12 dimensions organized under the following 5 domains- Programmatic Features, Engagement/Interest, Content Knowledge & Competence and Reasoning, and Career Knowledge/Acquisition & Attitude/Behavior.