Performance insights by Deakin’s Centre for Sport Research. Please feel free to contact the author of this work, Aaron Fox (aaron.f@deakin.edu.au), if you have any questions about the analyses.
The introduction of rolling substitutions into Suncorp Super Netball this year has potentially made identifying the best line-up combinations and most appropriate substitution strategies even more important than previous seasons. The greater number of line-up combinations being used also means metrics like plus/minus (herein referred to as ‘+/-’) can be used more readily in examining Suncorp Super Netball performance.
For those unfamiliar, +/- tracks the goals scored for and against a team when a player (or an entire line-up) is on the court. The metric appears to have its origins in the National Hockey League, where a trophy was awarded to the +/- leader for the season each year (ceased in 2008). It has, however, become more readily used in sports where more frequent scoring occurs (e.g. basketball).
Theoretically, +/- represents a measure of how well your team does when you’re on or off the court, and can be adapted to consider entire unique line-ups. It’s important to consider that an individual player’s +/- could be impacted by a number of things unrelated to them. For example, if your team has a dominant centre court player and your role is to relieve them - it may be that the team’s performance drops while you’re on-court, but only because you’ve subbed the star player out. Conversely, a player may incur a high +/- because they regularly play with the good players (and don’t make huge contributions themselves). It is not a perfect metric, but when considering a large portion of data (e.g. a seasons worth) it can likely identify the best line-ups for each team. An additional application of +/- is to compare the metric when a player is on or off the court. The differential between a players on vs. off +/- may be a good indicator of their importance to their team (i.e. a high positive differential means a team is much better when the player is on-court).
Here we will present two versions of +/- for line-ups and players. First, absolute +/- represents the total score differential for a line-up or player. This doesn’t take into account the amount of time the line-up or player is on-court. To account for this, we present a relative +/-. This divides the line-up or players +/- by 15 minutes, and therefore represents the average +/- you could expect for a quarter of play.
Data through 6 rounds of Super Netball 2020. Source: Champion Data Match Centre
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