# Predicting Player Churn of a Free-to-Play Mobile Video Game Using Supervised Machine Learning
## 1 Introduction  
Game design and development have come a long way since their humble beginnings, from very simple 2D platformers, 3D games of various genres, to today's realistic, breathtaking graphics and immersive virtual reality games. It is difficult to determine which gaming genre or platform is the most popular, as player preferences and demands vary and change quickly. Developers need to adapt as the active playerbase determines the success of a game. With the evolution of the Internet, games have become easily accessible and advertsible, the popularity of multiplayer games has skyrocketed, and countless players now share their feedback over forums and other platforms. Similar to the evolution of the games themselves, monetization tactics have evolved accordingly. Before the Internet was stable and fast enough, most games had a set price--once a customer bought a game, there was no need for additional purchases. In some less frequent cases, developers released additional downloadable content (DLC), which could extend a game's features for a price, usually less than the cost of the game. Later, the massively multiplayer online role-playing game (MMORPG) genre took a different approach--monthly subscriptions. The most notable example is _World of Warcraft_ (WoW), in which the subscription model worked due to the game's unrivalled popularity (WoW reached 12 million subscribers in 2010 [1]). Less-popular MMORPGs could not afford to use such a model, as players were often unwilling to pay monthly subscription fees. Consequently, game providers would offer the game for free, while offering players the option to purchase cosmetic items or some kind of boost which would give them an advantage over non-paying players [2]. This business model has grown to be widelyregarded as the F2P (free-to-play; also referred to as freemium [3]) model, and has proven to be very successful in a wide range of PC, console, and mobile games. Studies have shown that if a F2P game offers in-game purchases, the vast majority of players tends to spend no money, or a very small amount, on virtual goods inside the game [4]. According to the 2019 Swrve Monetization Report, providing an in-depth study of player spending habits in freemium mobile games, only 1.6% of players make an in-app purchase, while 72% of paying players make only one purchase [5]. Consequently, a very large portion of the profit is generated by a very small percentage of players, which have been referred to in the past as \"whales\", with studies having found the majority of such players to fit to the gamer stereotype of being young males [6]. The term \"whales\" was originally used in a negative way, as developers used it to describe customers who are so wealthy, they could sell anything to them. The term is still used in the gaming community, albeit not in a negative manner, but rather to refer to players that simply spend a lot of money on the game [7]. It has further been argued that rather than such players being spenders which can afford anything offered to them, mostly they are simply unaware of the actual amount they have spent on the game, likely due to the large number of low-value transactions [8]. Given player spending habits and the monetization potential of the F2P model, it is clearly important for game publishers to identify and create content that will appeal to paying customers, so as to keep the players playing the game and maximize achieved revenue. The other relevant revenue stream for developers is marketing--players are shown commercials, commonly for other games from the same developer, or from other developers. For this business model, it is also imperative to keep the players engaged as much as possible, so that more commercials are shown to them, thereby yielding increased revenue from this model. The question arises as to what implications marketing decisions have on player spending habits and potential churn, calling for the need to micromanage the combination of these two revenue streams.