Understanding Game Balance with Quantitative Methods

Game balancing is the fine-tuning phase in which a functioning game is adjusted to be deep, fair, and interesting. Balancing is difficult and time-consuming, as designers must repeatedly tweak parameters and run lengthy playtests to evaluate the effects of these changes. Only recently has computer science played a role in balancing, through quantitative balance analysis. Such methods take two forms: analytics for repositories of real gameplay, and the study of simulated players. In this work I rectify a deficiency of prior work: largely ignoring the players themselves. I argue that variety among players is the main source of depth in many games, and that analysis should be contextualized by the behavioral properties of players. Concretely, I present a formalization of diverse forms of game balance. This formulation, called 'restricted play', reveals the connection between balancing concerns, by effectively reducing them to the fairness of games with restricted players. Using restricted play as a foundation, I contribute four novel methods of quantitative balance analysis. I first show how game balance be estimated without players, using simulated agents under algorithmic restrictions. I then present a set of guidelines for using domain-specific models to guide data exploration, with a case study of my design work on a major competitive video game. I extend my work on this game with novel data visualization techniques, which overcome limitations of existing work by decomposing data in terms of player skill. I finally present an advanced formulation of fairness in games—the first to take into account a game's metagame, or player community. These contributions are supported by a detailed exploration of common understandings of game balance, a survey of prior work in quantitative balance analysis, a discussion of the social benefit of this work, and a vision of future games that quantitative balance analysis might one day make possible.