Assessing player performance in Australian football using spatial data
This thesis creates a new method for assessing player performance in Australian football, specifically for an application to the Australian Football League (AFL) Data have been captured by Champion Data as the official statistics provider to the AFL since 1999. More than 100 event types are recorded for each game, such as possessions, disposals, tackles and goals. Up to 50 variables are available to describe the context, quality and location of such events. A full investigation of this information was performed to extract relevant traits of the data, and to improve on existing methods of analysis and available knowledge within the industry. Two outcomes of this exploratory analysis were a visual representation of data through the use of heatmaps, and a new measure for kicking ability called 'kick rating' Heatmaps have been used by AFL clubs since 2008 as a way of communicating information to players and extracting information about team and player tactical traits. Kick ratings have been used by AFL clubs since 2011 as a development tool for their own players, and for scouting of opposition players. The data were also compiled into a player performance measure 'Equity Ratings' where the spatial locations of each event acted as a basis for evaluation. For each event, the rating system calculates the equity of the player's team before and after the event to measure the objective contribution that the event made to a team's position.