sdiinc's Blog

Critique My Method (NHL)

By sdiinc | View all Posts
Posted Friday, November 14, 2008 12:43 PM   54 comments
Ladies and Gentlemen,

This will be my first full season working with NHL data.  I'm using a formula very similar to the MLB underdog formula which has worked extremely well for me for the last two years.  I compare the road team's average points scored on the road against the home team's avg points allowed at home, and vice versa, and then have a second formula that weighs the net performance of the team against their strength of schedule to get an output similar to Sagarin's rankings.

The final step is a comparison of my expectations to the line in an attempt to find a moneyline value. 

In short, we're looking for underdogs with a big ML but a reasonable chance of upset.  The determination of value is made by dividing the ML into 50%, which tells me the frequency of wins necessary to break even.  There is an extensive discussion of my method in this regard on my thread 'Critique my Method (MLB)'.

In MLB I started off with a progressive method, and used this to great success.  However, due to binomial distribution, you're bound to end up with some long losing streaks, and this can lead to some big bets. 

Therefore, I'm going to attempt to increase the total number of events and stick with a fixed-amount per event.  The upside is we eliminate the risk inherent in any progressive system, the downside is you lose the benefit of eliminating losses with an immediately succeeding win, a rather frequent occurence when the stats are approximately 50%.  Again, check the MLB thread for an extensive, season-long discussion of this.

That having been said, I will always post picks in order of favorite to least-favorite in terms of the final value proposition of the event.  I know some of you will just email and ask me which is my favorite anyway.

14 Nov 08 Underdogs:

Nashville @ 165
Florida @ 140
54 comments
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gasman33 says:
11/14/08 10:30PM
well.....so far...

 


Nashville @ 165...pending
Florida @ 140....

 

...

gasman33 says:
11/15/08 10:57AM

well.....for the night...

 


Nashville @ 165...
Florida @ 140....

 

........1-1

 

...

sdiinc says:
11/15/08 11:52AM
NAS @ 130
NYI @ 135
sdiinc says:
11/16/08 11:15AM
YTD 3-1, +3 units

16 Nov:

LA @ 177
TB @ 125
gasman33 says:
11/16/08 11:52AM
Tomspeople says:
11/16/08 12:05PM


You're actually up 3.3 units :P
openbahr says:
11/17/08 07:07PM
I'm assuming according to your criteria... If you made a pick tonite, it would be edmonton
sdiinc says:
11/17/08 09:06PM
17 Nov:

NAS @ 122

Edmonton is a bigger ML play, but I show Detroit as a much stronger favorite than San Jose.  The difference in my formula being that I look for a margin of victory of less than 1.
sdiinc says:
11/18/08 11:49AM
18 Nov:

COL @ 130
MIN @ 120
FLA @ 135
openbahr says:
11/18/08 03:07PM
I think phoenix  would be a great pick for your system tonite too
sdiinc says:
11/19/08 12:07PM
YTD 5-5 +1.5U

19 Nov

WAS @ 120
VAN @ 130
sdiinc says:
11/20/08 11:20AM
YTD 7-5, +4 u

20 nov:

EDM @ 125
VAN @ 160
FLA @ 125
Osiris2012 says:
11/20/08 11:52AM
Got it!  
sdiinc says:
11/21/08 01:27PM
YTD 8-7, +3.6 units

Nov 21:

NAS @ 110
openbahr says:
11/21/08 02:50PM
love that pick!!  nas should be favored imo
sdiinc says:
11/22/08 12:18PM
Nov 22:

BOS @ 135
sdiinc says:
11/23/08 05:17PM
YTD: 9-8, +3.95u

Nov 23:

Only one game today, no selection.
sdiinc says:
11/24/08 03:07PM
Nov 24:

WAS @ 145
PHX @ 136
sdiinc says:
11/25/08 01:13PM
Nov 25:

LA @ 151
sdiinc says:
11/26/08 12:01PM
Nov 26:

STL @ 168
PHX @ 123
LA @ 152
Stake24 says:
11/27/08 07:25AM
nice work sdiinc
sdiinc says:
11/27/08 11:55AM
Nov 27:

TOR @ 122


sdiinc says:
11/28/08 02:34PM
YTD 11-13, +1.5u

Nov 28:

FLA @ 134
sdiinc says:
11/29/08 12:18PM
This is a first for me, losing 3 in a row in OT shoot-outs.  I've tried to run the odds on that happening and it's somewhere around 7/10ths of a %.  Oh well...

Alot of good data to work with today, so a number of opportunities.  Have a great day!

Nov 29:

VAN @ 120
BUF @ 135
NY @ 125


desertfx says:
11/29/08 07:49PM
thnx 4 your info hope it works out for us
sdiinc says:
11/30/08 12:23PM
Nov 30:

FLA @ 191
sdiinc says:
12/01/08 11:50AM
We ended November with our biggest win of the season yet, a 191 ML on FLA.  Our total tally for the month was 13-16 (45%), a gain of 1.66 units. 

Over the course of the season my target for the underdogs is 50%, which should yield a gain of approximately 5.5 units over the same number of events.

Dec 1:

VAN @ 104
TOR @ 121
sdiinc says:
12/01/08 11:51AM
I will be traveling on Dec 2 and unable to post,  See you on Wednesday.
sdiinc says:
12/02/08 02:21PM
Got lucky and found a WIFI spot.

Dec 2:

TB @ 161
CaseyJonesWW says:
12/02/08 03:29PM
TB is undervalued for this game. They should win over 38% similar matchups to break even (I put them at ~ 120 so I love the value).
sdiinc says:
12/03/08 11:47AM
Dec 3:

DAL @ 132
ATL @ 174
sdiinc says:
12/13/08 11:23AM
Dec 13:

DAL 150
BUF 130
CAR 125
TB 135
PHO 125
sdiinc says:
12/13/08 11:28AM


Sure, this is true.  Each event is statistically independent.  However, it is also true through binomial distribution (as I mentioned in my first post), that you can predict with certainty over a large number of events how likely a certain outcome is.  For example, if you expect an event 50% of the time, you can predict how likely you are to be wrong say, 5 times in a row.  The formula is:

.5 x .5 x .5 x .5 x .5 =  3%

So while the gambler's fallacy is true (I love the irony), over a large number of events you can expect a low standard deviation.  The problem with stops is there is usually no rhyme or reason behind their use, i.e., where they are employed.

I used the progressive system to great success the last two MLB seasons, but have decided to stick with straight bets and increase the total number of events.
sdiinc says:
12/16/08 12:06PM
DEC 16:

MON @ 108
STL @ 130
sdiinc says:
12/16/08 12:15PM


The 'stop' you have described is, in fact, arbitrary.  It is based only on the objective you hope to accomplish, viz., winning.  It is not based on a statistical probability that you expect based on a formula.

Of course, I do agree about the slim possibilities of a 10 game losing streak, but you can easily calculate the probabilities based on say, 50% per event:  .09%.

As to your question, I don't think you've read the full thread.  There are no 'stops' here, because we are not using a progressive system.

In the MLB, we used no stops, because as I've indicated here, they're purely arbitrary and have no mathematical basis for placement.  As I asked previous questioners, how do you choose whether it's 4, 5, 10 or 20?  The immediately succeeding event would have a far higher probability than it's predecessor, so I don't see how you choose.  Case in point is the example you've used, i.e., 10 game chase, where the probability of a 9 game losing streak is 0.195% and the 10 game losing streak is 0.098%

Over the course of the MLB season our longest losing streak was 7.  We had several of 4.  2 and 3 game streaks were common. 
sdiinc says:
12/16/08 12:19PM


This guy 'milkman' still can't get his math right.  Whether it's W-L or net units, he's always wrong somewhere.  Anyway, I've noticed he doesn't post when there are a few back to back wins, but waits for back to back losses and then jumps in.  Scan his posts on other threads-never anything constructive! 

What are the probabilities it's a pseudonym for another user?  I'd say about 78.5%
sdiinc says:
12/04/08 05:44PM
Dec 4:

PIT @ 119
COl @ 130
NJ @ 114
sdiinc says:
12/05/08 07:57PM
Dec 5:

STL @ 124
VAN @ 142
sdiinc says:
12/06/08 10:56AM
DEC 6:

MIN @ 120
ATL @ 110
sdiinc says:
12/07/08 04:14PM
DEC 7:

PHO @ 162
sdiinc says:
12/08/08 05:26PM
DEC 8:

FLA at 162
sdiinc says:
12/09/08 11:10AM
Dec 9:

NY @ 220
sdiinc says:
12/11/08 12:35PM
Dec 11:

CAR @ 149
sdiinc says:
12/17/08 10:25AM
DEC 17:

EDM @ 145
sdiinc says:
12/17/08 10:41AM


I understand what you're saying.  I would consider an individual's unit risk management strategy as a different issue than the question of progression.  If you consider them as a whole, however, I would agree that it is no longer an arbitrary question.  I find that most gamblers bet far too much per event, and I personally have tried to move towards 1% per event.

You're right about CLT, I tried to address this more simply using binomial distribution. If I'm using thousands of events but applying that to only, say 150 or so in a season, there can be a substantial deviation.  The only way I know how to counter this is by increasing the number of total bets while maintaining a comparable confidence per event.
sdiinc says:
12/18/08 10:36AM
DEC 18:

SJ @ 122
sdiinc says:
12/19/08 02:24PM
DEC 19:

OTT @ 135
sdiinc says:
12/20/08 05:31PM
DEC 20:

BUF @ 153
sdiinc says:
12/21/08 09:28AM
DEC 21:

PHI @ 115
sdiinc says:
12/22/08 10:52AM
I'm taking a break for the holidays.  Have a Merry Christmas!
Sumtingwong says:
12/12/08 01:20PM
A comment here on the money management system and Gambler's Fallacy.  Basically, it states that every event is statistically independent and not related.  Perhaps a stop needs to be put in place at a certain point?
Sumtingwong says:
12/16/08 04:01PM
sdiinc,

I have read all your threads; that is how I emailed you and determined that you trade financial instruments for a living--please look at the second email I sent you.

Yes, the stop is arbitrary for a group or a system, but not for an individual based on their bankroll and risk profile.  

I ran the numbers and everything is very straightforward.  The only thing that you need to worry about, stats-wise, is that your sample is greater than 30 when compiling your data for a selection--this comes from the Central Limit Theorem.  The Central Limit Theorem can also be used for a selection based on the last 30 plays: if the 50/50 plays are several standard deviations from the norm, a play in the opposite direction may be wise.  Also, as is almost always the case, more data = better results.  
Sumtingwong says:
12/13/08 03:45PM
A stop should not be arbitrary and risk must be managed and predefined for each bettor.  For instance, if you are up 10% betting the NHL, a chase could encompass all your winnings for the year until the bankroll is even.  At this point, the chase stops.  If the chase happens to run to 10 bets based on the 10% winnings, standard deviation tells us that this is a slim possibility and there should be a win in there somewhere.  

I am curious as to your methodology for trading: what stops were placed and why?  Are they any more arbitrary than here?  Did you chase bad trades?  

I am sweeping away the cobwebs on the stats and running some numbers.  Will post when through.  I think there is a confidence level that may come into play as well.  

All said, if your system is working, keep rolling.  
bluejays99 says:
12/14/08 12:22PM
Milkman instead of evaluating how other systems perform. Why don't you try to evaluate the value added that you bring to this forum. I can help you out with that one. It's zero.
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User: sdiinc
Joined: July 2008
Location: Tennessee
Team: Tennessee Titans
Occupation: Accounting/Finance

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