Friday, July 5, 2013

Expected Wins vs Actual Wins

When we started our Expanded Standings project in May, we knew that it would take us beyond just the simple statistics of Wins and Losses into all kinds of different areas. One of the more interesting items we have been quietly tracking is called the Pythagoreon Expectations or Expected Wins for each team.

Pythagoreon Expectations was developed by Bill James who is a renowned statistics expert in that other summer sport, Baseball. What does Baseball have to with Lacrosse? Well not much but Mr. James did find that you could fairly accurately determine a team’s season end win total if you calculated their run differential throughout the season. In short, the good teams nearly always scored more runs than they gave upand the best teams did it by a wide margin. Pretty simple and easily translated to other sports since the same corollary of “better teams score more than they give up” is true in Hockey, Football and Lacrosse.

For Lacrosse, we often decide ties in tournaments and leagues by using the Goal Formula. For a refresh:
Goal Formula = Goals For/ (Goals For + Goals Against)

The Pythagoreon Expectation (PE) formula gives you an idea of how many games a team “should win” based on their scores throughout the season. The PE is an adjustment to the above Goal Formula:
PE %= (Goals For ^2.37)/((Goals For ^2.37)+(Goals Against ^2.37))

            Taking a simple formula and using the exponent of 2.37 gives us a rough idea of the expected winning percentage for a given team based on their Goals For and Goals Against. It does not adjust for certain items like injuries or trades (heck every team has to deal with them and at some point you just are what you are as a team regardless) but it also shows that some times a team’s record is less than it should be because of factors they cannot control like timing of injuries and luck.

            Now lets take a peek at both the Ontario and BC Expected Wins as of July 4:

Ontario                                PE%  ExW               
Six Nations Arrows
Burlington Chiefs
Whitby Warriors
Orangeville Northmen
Peterborough Lakers
Barrie Lakeshores
Brampton Excelsiors
KW Braves
Toronto Beaches
St. Catharines Athletics
Mississauga Tomahawks

BC                                             PE%   ExW
Coquitlam Adanacs
New Westminster Salmonbellies *
Langley Thunder
Victoria Shamrocks
Delta Islanders
Port Coquitlam Saints
Nanaimo Timbermen *
Burnaby Lakers

Ontario Notes:
            Burlington (12.7) and Peterborough (12.4) both show at around 12.5 Expected Wins based on the PE formula but the Chiefs have exceeded that expectation while the Lakers are lagging. Orangeville looked to be well ahead of pace before their recent 3 game losing streak brought them back to reality.
            The one Ontario team that has seen some recent volatility in this measure are the Brampton Excelsiors. Ten days ago the maroon and gold were even with Peterborough and Burlington for roughly 12 wins. Then they have a bad week and drop down to an expected 10.5 wins. We are willing to give the Excelsiors the benefit of the doubt for an off week but they are worth monitoring further.

            The Arrows have clearly pushed ahead and now look like the team everyone expected in May. The Beaches have managed to turn around a horrible start but they will run out of games in their efforts to catch KW. Barrie’s great start will earn them a playoff berth and a date with either Whitby or Six Nations in the first round.

BC Notes:
            Not unexpectedly, the Adanacs and Salmonbellies are the class of the west. Even with a forfeited game the Bellies look good for their expected win total.

            Delta’s deadline trade of the league’s top two scorers in Cody Nass and Eli McLaughlin netted a huge haul of prospects and draft picks. It also leaves one wondering why? They stand fairly even with Victoria and Langley in PE% which means they should have an even chance against either opponent in a first round playoff series. Though with Coquitlam and New West the dominant forces, perhaps cutting bait and building for 2014 was the best course of action.

            Pity poor Nanaimo. With one win on the season they have underperformed their Expected Wins quite severely. They will be the ultimate test going into 2014. Are they as bad as their record or does the PE% number foreshadowing better times ahead for the Timbermen?

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