The [ppm] eyrie

September 17, 2009

The key factor

Filed under: powerplay manager hockey, PPM.statistics — glanvalleyeaglets @ 12:08 pm

Let us put the tactics and game importance aside for a while and ask: what is the most important factor that decides the outcome of a game? Today we’ll talk team strength. Whether we like it or not, as much as we sometimes wish an underdog to win, the stronger teams usually do better and prevail in the long run. The ice-hockey simulation in powerplay manager is no exception.

One could write monographs about what makes a great team great. Luckily, it is easier in PPM. Each team has a profile page where you can find the estimate of team strength based on the lineup used in the previous official game. These are the ominous “stars”, the four integers indicating the levels of Goaltending, Defence, Offence and Shooting. There is a fifth one that shows the total team strength, but it is just the arithmetic mean of the former four. So let us look at the four numbers as a measure of team strength.

There is a long ongoing discussion about “what do you mean by saying that your team was much stronger”. With the scale going up to 200, it doesn’t sound like a big difference between 15 and 20, it is a basic beginners level. In the same time the difference between 15 and 20 is 25% down or 33% up, and this is no peanuts anymore. We can see whether our team is better or worse in terms of the stars, but how does it affect the chances of winning the bloody game? Be the first to know and keep reading this great feature article in the [ppm] eyrie. We bring to you the whole story as it unfolds! Blah, blah, blah!

A typical ppm ice hockey team in the middle of second season might have Goaltending GT rated at 16, Defence DF=16, Offence OF=15 and Shooting SH=14. My Eaglets have (23, 23, 22, 19); Radowan’s Enterprise is currently rated at (30,25,28,17), the best Latvian team Pardaugavas Lauvas impresses with (31,29,23,22).

We’ll do the simplest thing out there and just sum the four indicators (GT + DF + OF + SH) of both teams and compute the difference, and see how the teams perform against each other in dependence on this difference.

The results can be summarized in a table. The first column shows the difference, then the percentage of wins (in regular time), overtimes and losses of the stronger team and finally the number of games used to calculate the “odds”.

Diff W % OT % L % N
1-2 47.3 15.0 37.5 7588
3-4 51.8 14.5 33.5 7176
5-6 56.8 14.2 28.9 6153
7-8 62.0 13.4 24.4 5363
9-10 68.0 11.9 20.0 4609
11-12 72.3 11.0 16.6 3906
13-14 77.5 10.1 12.3 3412
15-16 81.7 8.0 10.2 2865
17-18 84.4 8.0 7.4 2298
19-20 88.6 6.9 4.4 1859
21-22 90.2 5.7 3.9 1512
23-24 92.9 4.2 2.7 1199
25-26 94.6 2.4 2.9 892
27-28 95.8 1.6 2.5 718
29-30 96.8 2.2 0.9 540
31+ 99.8 0.1 0.0 5199

The trend is visible, isn’t it? The advantage of some 6-7 team strength points weighs approximately as much as the correct counter-tactics. I hope to get to the corresponding effect of game importance in a future article.

How does this info add to the understanding of the game? Let’s speculate and assume that I am to throw my 87 points against Liepinsh’s 105. Under normal conditions I’m at -18 meaning that my chances of winning the game are somewhere around 7.4%. Can I influence my odds? Sure, I can choose the game importance and tactics. With the right counter-tactics, the odds would shift in my favor, perhaps the shift is worth as much as 6 points making the gap approx. -12 points wide. Why, according to this arithmetics, the chance of winning just sky-rocketed to 16%! If I am lucky and my team actually plays that tactics well and if I use higher game importance, my chances might improve even further. (Of course, the life is never as simple as that) 🙂

Just want to make a final remark. Perhaps I am looking at the wrong thing. The quotient of team strength indicators might be more important than the difference. Say, is the difference between 110 and 100 points “ten points” or “ten percent” wide? Is it as good as 20 vs 10 (difference) or as good as 11 vs 10 (quotient)? Or is it something in between? I don’t know the answer, but some day…

September 16, 2009

Tactics and home ice advantage

Filed under: powerplay manager hockey, PPM.statistics — glanvalleyeaglets @ 10:41 am

In the first season I was first and foremost interested in finding out the basic relations of the tactics and countertactics, so I only recorded the tactics and the score of the match. As the spread in the teams’ strength increases, the grand total tables make less sense, so I decided to create a more serious databasis for the second season. So for each game under consideration I store the tactics, game importance, team strength estimates (the “stars” for goaltending, defensive, offensive and shooting), shots, penalties and the final score. I find this is a much better tool for studying how this game works!

I hope this is the first post in a series of articles. Today I want to address a simple question: is there a home ice advantage in regular season games and what does it have to do with the tactics?

Let us start with the grand total table using all the games I’ve gone through. All are from the regular tournament of the second season, match days 1-16 (games with participation of inactive teams were excluded, but it was done with care in order not to lose games like this one 🙂 ). In total 48,770 games of powerplay manager ice-hockey. For those interested: the most popular pairing of tactics is Normal vs Normal with 5083 games; the most exotic is Defensive (home team) vs Breaking up (road team) with 416 games. Here the rows represent tactics of the home team, the columns – the tactics of the road team. The numbers are percentage of home wins, games with overtime and away wins.

Normal Offensive Defensive Counteratt Breaking Forecheck
Normal 48.1-11.4-40.3 42.3-11.8-45.8 63.1-10.4-26.4 47.1-13.5-39.2 37.8-10.1-52.0 45.8-10.8-43.2
Offensive 54.4-11.5-34.0 48.9-12.1-38.8 37.5-13.0-49.3 48.0-13.3-38.5 52.8-10.3-36.8 62.7-12.0-25.1
Defensive 37.8-12.5-49.6 59.6-12.4-27.9 48.0-12.3-39.6 51.0-11.6-37.2 47.8-11.7-40.3 43.6-13.2-43.0
Counteratt 49.3-12.0-38.6 48.1-12.6-39.2 47.6-11.3-40.9 48.0-13.2-38.6 58.1-11.8-30.0 37.0-9.0-53.8
Breaking 61.9-8.9-29.0 46.7-12.5-40.6 42.3-12.6-44.9 34.5-12.5-52.8 45.0-11.8-43.1 45.3-9.8-44.8
Forecheck 51.4-11.6-36.8 35.0-12.1-52.7 44.5-11.2-44.2 61.1-12.8-26.0 51.1-12.2-36.6 47.8-13.0-39.1

The home teams win approximately 48% of the games and lose some 40%, so there is a measurable home ice advantage in this game.

The average team in this study has goaltending rated at 16.1 stars, defense 16.0, offense 15.4 and shooting 14.1. No wonder that, for instance, offensive tactics overall does slightly better than defensive tactics (it is worth paying more attention to the weakest part of the team). For offensive teams, the opposite is the case!

On the top of this we clearly see the famous ring of countertactics in action!

Of course, games of equally rated teams are more interesting to us. Taking the sum of goaltending, defense, offense and shooting “stars” as a measure of team strength and filtering out all games where the difference exceeds 5, I was left with mere 18,508 games. Here is the resulting table:

Normal Offensive Defensive Counteratt Breaking Forecheck
Normal 49.5-14.5-35.9 46.8-15.7-37.4 65.9-12.0-22.0 50.4-15.4-34.1 38.7-12.0-49.1 47.5-12.9-39.5
Offensive 48.8-15.2-35.8 46.7-16.2-37.0 36.1-17.6-46.2 48.6-16.2-35.1 51.9-13.7-34.2 60.6-15.1-24.1
Defensive 34.5-16.5-48.8 63.3-14.3-22.2 45.9-14.2-39.8 45.8-16.2-37.9 49.4-11.7-38.8 43.4-17.3-39.1
Counteratt 51.4-13.7-34.8 52.0-15.2-32.7 48.2-14.5-37.1 47.7-16.5-35.7 60.0-12.8-27.2 36.3-12.1-51.5
Breaking 62.0-11.5-26.4 50.1-13.5-36.2 45.9-13.1-40.9 31.5-16.3-52.1 45.6-12.8-41.5 49.5-11.6-38.8
Forecheck 52.0-15.0-32.8 37.4-16.7-45.7 43.4-15.6-40.9 63.2-15.8-20.8 49.3-13.8-36.7 50.7-16.2-32.9

We see that in this case the draw margin is way bigger and that it is harder for the visiting team to win the game; home wins ~ 48%, away wins ~37% of the “equal” games.

I must stress that these tables are not there to suggest that “some tactics are better than others”. It is true that the tactics should suit your team and tactics that one team uses with great success may miserably fail for another team with different skill distribution.

So we have seen the importance of home ice in games of the regular season. It is claimed that there is no such thing in cup games or friendlies. In the next article I plan to go deeper into the overall team strength – performance relation. It will turn out that the team strength may be more important than the tactics 🙂

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