Dan Roy: When designing a new game, we go through many rounds of prototyping and playtesting. We usually start on paper, and then build digital versions over time. We play these prototypes internally first, then invite our target audience to join us in the studio, and sometimes go to schools, libraries, or community centers. We tell players very little before they start, and let them guess and ask questions along the way. We’re always teaching two things simultaneously – the subject and how to play the game. We watch for what players expect the game to do and where they get stuck. We often build in levels, so players can find the right degree of challenge for them. If players can succeed at the game, they are usually demonstrating mastery of what we hope they’ll learn. Just to be sure, we ask them what they’re thinking both while they play and afterwards to see how they’re hypotheses evolve. In structured pilots, we sometimes do pre- and post-tests to measure learning. In the final versions, we track performance to report back to players and teachers.