Over-round 2019-20

With the imminent return of English Premier League football, it seems a good time to dampen everyone's enthusiasm and point out that Pinnacle's average over-round since the start of the year for these matches has jumped up to 103.7%. 

For comparison, it was 102.8% for August to December, and last season was 102.4% following seasons of 102.1% and 102.0%. 

A concerning trend for those who take their sports investing seriously, although still a huge improvement from the 2000-01 days of 112.5%! Did anyone other than the rare and lucky accumulator winner ever make a steady profit against this margin? 

Such variations over the years make direct comparisons from one season to another irrelevant, but we can standardize the over-round and work with adjusted prices. It's not perfect but it gives a more accurate comparison than using the raw numbers.

For example looking at the returns from backing the Draw in the EPL since 2000-01, using the raw numbers (and prior to Pinnacle's Closing Prices from 2012 I used 2000-02, William Hill from 2000-02, and Bet 365 from 2002-12), backing the Draw in every match would have cost you 555.77 units.

Using the imperfect over-round adjusted to the current 103.7%, the loss from those 7508 matches is 290.12 units, which readily illustrates the impact the over-round has on returns. 

The table below shows the results for all blindly Backing outcomes:

Fortunately it is blindingly obvious that some bets are always just terrible value, and if you stay away from these, you are at least in with a chance of being profitable. 

Interestingly the over-round in the Bundesliga.1 since the break averages 102.7%, down from 103.2% before the stoppage. The welcome plight of Home teams continued this past weekend with only one such team (Bayern Munich) winning, making Home teams just 11 of 55 since the restart. I'll update the Bundeslayga numbers at the end of the season.