There's no perfect method. Good article from OPTA below:Snowflake Royal wrote:That seems somewhat flawed as a system.tmesis wrote:Possession is just a percentage of the passes each team made, so it should add up to 100.Nameless wrote:LOL at people worrying that the possession stats don't add up to 100. It makes little sense for them to add up to 100.
Perfectly possible for neither side to have possession of the ball at times. It's only a guesstimate anyway......
http://www.optasports.com/news-area/blo ... essed.aspx
tl;dr - trying to determine who has possession at any given second requires two people to concentrate for the whole 90 minutes. Just relying on the passing ratio generates very similar answers but doesn't fail when someone drifts away.