Saturday, June 18, 2011

Sporting KC and Home Field Advantage in Soccer: A Luchametric Quickie


Last night Sporting KC got its first home goal and its first home win, beating a surging San Jose club at Livestrong Sporting Park 1-0. We had predicted a SJO win, what with their lead-leading 1.54 Goals For per Game average going into the match, and their excellent recent form: 4 wins and a draw in their last 5 matches.  But KC looked better than we've seen them all year and prevailed in what we thought was a tight match.  In thinking about what we had missed in our analysis of the match, we realized that we had forgotten the most fundamental truth about professional soccer and about wagering on professional soccer: the 50/25/25 rule.

What's that you say? The facts are that in top leagues across the globe, including the EPL and the MLS, all things being equal, the home team will win 50% of the time, the away team 25% of the time, and the teams will draw 25% of the time.  That this is so is just part of the deep fabric of the game, decreed by the soccer gods long ago.  There have been various reasons put forth for this phenomenon, to travel demands on players, familiarity with the pitch, to the energy of the home crowd supporting the home team.  But we'll save any in-depth discussion of home field advantage for another post.

Here's the quickie.  Going into last night's match, KC had played 12 games, 11 of them on the road. In a normal season, half of those 12 games would have been at home, where (again, all things being equal) they would have won a full 50% of those matches (let's call it 6 home games just to make our back-of-a-napkin analysis easy).

Applying the 50/25/25 rule, KC's point total from 6 home games and 6 road games would be 10.5 pts from the home matches (3 wins and 1.5 draws) plus 6 pts from the road matches (1.5 road wins, 1.5 road draws) for a total of 16.5 pts total, not the 10 they were sitting on going into last night's match.

The point is that playing on the road for 11 games to open the season has distorted KC's record considerably, by about 34% or more.  This means they are a considerably better club than they've been given credit for.

Playing on the road in any league is tough, resulting in fewer chances created, more chances allowed, more mental mistakes, etc. KC has more home games left in their schedule than any other club.  Their PTS/GM will inevitably go up.  They will beat clubs at home that are substantially higher than them in the standings.  The only caveat to the 50/25/25 rule is that if two teams are not equal in strength, then the percentages get adjusted to the point that with two very uneven teams, the numbers change to 65/17/17 or even higher.

Our claim is that KC probably belongs in the middle of the pack, not down at the bottom with the likes of New England, who have no excuses.

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