Today's economic situation demands that learning organizations become more diligent in their business dealings to reduce cost and increase bottom line for survival. While there are many champions and proponents claiming that game-based learning (GBL) is sure to improve learning, researchers have, thus far, been unable to (re)produce concrete, empirical evidence supporting this claim. Lacking appropriate assessment methodologies to showcase the effectiveness of the learning technology and to convince stakeholders that GBLs could really work, it is no wonder that many learning organizations regard GBL training as a potentially high-risk technology investment. This paper describes a GBL assessment methodology designed specifically to collect player-generated data in an in situ manner (i.e., within the game environment itself) through telemetry. This methodology further incorporate data visualization to translate the data collected into meaningful information and actionable intelligence for various stakeholders.