Sunday, May 28, 2017

Last features - and a summer freeze

During the month of May I added two new features for the website, naturally dedicated to the upcoming draft:

Draft Pick Stats
Draft Pick Success

Now it's time to step back, look around and improve the infrastructure behind the website, both in the matter of the collection and the publication of the data. Thanks to all the visitors both of this blog and of the website.

I will continue to publish my predictions for the remainder of the playoff games on Twitter - follow me @morehockeystats! You are also most welcome to send me your ideas for new unusual statistics.

So the projected plan for the summer months is:
June - improve and finally release the Perl scraper
July - improve the publishing mechanism for the website and speed it up
August - improve the Elo-based models behind the site's projections
September - add some new features

This blog is on no pause! I will continue to publish entries about my hockey-related thoughts as they come. Stay tuned!

Monday, May 1, 2017

On carrying Momentum...

Frequently, the importance of carrying momentum over an intermission can be heard being talked about. I thought it were possible to measure this harmony with algebra, so I tried to do that. I choose to analyze a very specific question:

If the regulation of a game ends in a tie, other than 0-0, how frequently would the team that tied the game with the last regulation goal win in overtime. 

We would define the team that tied the game as the one having the momentum. We would define the other team as the one trying to show resilience. For answering the question, we analyzed the outcome of games of seasons 2007/08-2016/17 (including the ongoing playoffs). We discard the games that end in a shootout, because their outcome depend truly more on the skill of the shooting players/goaltenders rather than the whatever momentum might've been accrued.

The results of the analysis are displayed in the table below, per season, per the time frame during which the last tying goal was scored: in the last two, five, or ten minutes, in the last period, or in one of the first two. The numbers show the percentage of wins by the team having the momentum and the number of games falling into that specific segment. Also we display a separate column and a separate row for playoffs game, although a finer granularity is not really possible because of the sample size.

Season   2        5        10       20       1st/2nd  total     totalPO
2007     54.2/24  57.9/19  52.9/34  53.8/13  52.6/38  53.9/128  31.2/16
2008     43.5/23  48.1/27  45.2/31  53.8/13  40.0/40  44.8/134  25.0/16
2009     42.9/28  56.5/23  72.7/22  64.7/17  53.7/41  56.5/131  58.8/17
2010     48.6/37  54.2/24  47.1/34  40.7/27  56.8/44  50.0/166  59.1/22
2011     50.0/24  45.8/24  43.5/23  72.0/25  47.7/44  51.4/140  37.5/24
2012     62.5/16  33.3/15  50.0/22  50.0/14  57.9/19  51.2/86   53.8/26
2013     58.1/43  43.5/23  34.6/26  45.5/22  44.1/34  46.6/148  70.8/24
2014     51.7/29  65.2/23  55.3/38  46.7/15  60.5/43  56.8/148  57.9/19
2015     60.0/40  46.7/30  44.4/36  45.8/24  39.6/48  47.2/178  52.6/19
2016     43.6/39  50.0/28  60.5/38  48.1/27  61.8/68  54.5/200  63.2/19
totalPO  61.4/44  46.7/30  55.8/43  68.4/19  40.9/66  52.0/202 52.0/202
total   51.5/303 50.4/236 50.7/304 51.8/197 51.8/419 51.3/1459 52.0/202

We see that there is no specific "momentum" nor "resilience" capability overall, there is practically no indication on how the OT would end based on which team scored the last GTG. The only two moderate exceptions with decent sample sizes are the second and the sixth columns of the penultimate row. The GTG-scoring team is 27-17 (61.4%) in case it scored the tying goal in the last two minutes, however if the GTG was scored before the last period, as it happened in 66 games, the momentum would obviously not carry over two or more intermissions, and the tying team is 27-39 (40.9%) in these games.

Here is how it looks on a graph:
We can see all lines wobbling slightly above the 50 mark. Insufficiently above. Even if we observe the extra 1.3% chance overall (2.0% in playoffs) - wouldn't it be more related to the home/away advantage? I haven't looked at this aspect yet. Maybe another time.

The Real Life[TM] took a bit of a toll on this blog... But we resume, with resilience and hoping to generate momentum!