This project is making novel use of familiar technology (smartphones and tablets) to address the immediate and pressing challenge of affordable, ongoing, large-scale museum evaluation, while encouraging museum visitors to engage deeply with museum content. Using a smartphone app, museum visitors pose questions to a 'virtual scientist' called Dr. Discovery (Dr. D). Dr. D provides answers and the chance to complete fun mini-challenges. The questions visitors ask are gathered in a large database. An analytics system analyzes these data and a password-protected website provides continuous, accessible evaluation data to museum staff, helping them make just-in-time tweaks (or longer term changes) to exhibit-related content (such as multimedia, lecture topics, docent training, experience carts, etc.) as current events and visitors' needs and interests change. The intellectual merit of this project is that it is building evaluation capacity among informal educators, advancing the fields of visitor studies, museum evaluation, informal science learning, and situated engagement, and is contributing to the development of novel evaluation techniques in museums. This project has many broader impacts: The Ask Dr. Discovery system is available to any venue that wishes to use or adapt it to their context. By enhancing the visitor experience and improving museum access to data for evaluation and data-driven decision making across the country, Ask Dr. Discovery has both a direct and indirect impact on museums and visitors of all types. This project is also training the next generation of STEM and education innovators by employing a diverse team of undergraduate students.