Deduction is when you start with a theory, and then test that theory out. Induction is when you make many observations, and then come up with a theory based on the pattern of the observations.
Most games that are labeled as "deduction" (Werewolf, Resistance, etc.) have a mix of both induction and deduction. VISITOR also has both, but we think it has more induction than deduction. We also wanted to differentiate it from Resistance-like games because its mechanic is VERY different.
More info: http://www.socialresearchmethods.net/kb/dedind.php
Asked by Paul