Sunday 9 October 2016

Sharpe Lines

The College Football Small Road Dog System had a good Saturday with eight of the ten likely qualifiers making the final cut, with BYU a late addition.

With lines being dynamic, qualifiers for a system like this will always be subject to change, and the list will vary depending on where you take your line from, and when you take it.  

Disqualified were Army, who moved out to +5.5, and Virginia Tech came in to -1.5 favourites, although not before I had backed them at evens getting 1.5. Sometimes these line moves will work out for you, sometimes they won't. 

The line on BYU moved to +3.5 before kick-off, making them an additional qualifier. The final list and results from yesterday were as follows:
Hopefully some of you made some money. For the 2016 season, the results now look like this:
I'll update the NFL version of the Small Road Dogs system next week after all the games for the round are complete. 

Sports Picks System ( @sportspickssys ) took a look at my NFL findings, calculating the Sharpe Ratio for various spread ranges.

The conclusion:
It means that using small road underdogs with a spread from 2.5 to 3.5 is the safest system to play.
Playing this range only is certainly where most (90%) of the profits are generated, 57.62 points out of 63.56 points, (ROI 12.4%) but the 4 to 5.5 range generated an extra 6.54 points with an ROI of 2.3%. 

It's not all about ROI and safety though, as this post in 2011 concluded:
Those who’ve spent a lifetime maximising ROI, I guess you’ve now realised that in a punting context, those who are able to grow their bank balance more significantly are, by most people’s definition, the more successful.
So, in summary...Return on Investment for show, Rate of Bank Growth for dough. £, not %.
The ROI% might be lower, but so long as it's positive, why leave money on the table? For those paying Premium Charges, and most sportsbooks will soon limit you if you are winning with a double digit ROI%, there is added value in a lower ROI%.

At some point the returns may not justify the time needed, but the American Football seasons are relatively short, and typically on set days of the week. The average number of bets over ten seasons is 73 for the NFL and 97 for College Football, and the 4 to 5.5 range is less than 20 a season. Unless you're the CEO of a multi billion dollar global empire, I'd suggest that most people would have time to place an addition one to two bets a week. 

I wrote about the success of Road teams in Divisional games last week, so it seemed logical to see how Small Road Dogs performed in Divisional (Regular Season) games. 

The result of combining two profitable systems are not surprisingly impressive. Looking at Small (less than 6.5 point) Road Dogs in Divisional Games only:
Three losing seasons, with 2013 the only painful one but important to note that the impressive looking ROI of 13.1% is boosted by the returns of 2006 and 2007, and since 2008 is down to a still impressive 7.5%.   

1 comment:

James said...

One thing I have noticed with Sharpe Ratio (SR) is that it is dependent on sample size. As sample size increases then all things being equal so does SR, which doesn't seem helpful to me.

SR = average yield / stdev yields

Try it with a spreadsheet. Have a set of yields that has the same average yield for 10, 20, 40, 80 and so on returns. You can achieve this with just two values and repeating throughout the samples. (e.g. 1.2 and 0.8 - it will give an average of 1.0 for simplicity)

Then calculate the stdev for the 10, 20, 40, 80 and so on and then do the SR calculation for each. You will see a rising SR.

I used to do an SR for daily yields and it was very low. Positive but low. I did weekly and it was higher, monthly higher still (over the magic 2.0) but I was still averaging the same yield.

I still use SR in my optimisations but I have other metrics too and take all of them together.