9 July 2013

The Pain Game: 5-year analysis (2008/09 - 2012/13) - Part II

This is the second of what will undoubtedly be a brief series of data dumps and inconclusive-yet-attractive charts aggregated over the last five (four and a bit...) NHL regular seasons, updated to include the bit that was the 2013 bit of a season.

Analyses of individual seasons (including explanations of the CHIP figures and their limitations) plus my previous aggregate analysis (aggreganalysis?) are at the following links:

2013 

Firstly, an updated ranking of teams by aggregate CHIP over the last five seasons (playoff teams highlighted; click to enlarge image):


Again, no obvious strong correlation between playoff qualification and the degree and quantity of injuries/illnesses suffered (see Part I for a more detailed representation of this).  Clearly still some quite wide differences in aggregate CHIP and MGL between top and bottom over the whole period.

As touched on in my end of season analysis, no great evidence to suggest that the incidence of injuries in the compressed season was greater than in previous years and the aggregate league CHIP figure as a proportion of the pro-rated cap was actually marginally the lowest of the five year sample.

The same figures grouped by division:


As was notable last year, the Pacific still appears to have suffered significantly fewer and less costly injuries (the four teams at the bottom of the aggregate CHIP table are all Pacific teams), the gap widening further since last year.  Just attributable to random variation over a relatively short period or a sign of better injury management or prevention by those teams (despite the complaining about travel schedules)?

2 July 2013

The Pain Game: 5-year analysis (2008/09 - 2012/13) - Part I

This is the first of what will undoubtedly be a brief series of data dumps and inconclusive-yet-attractive charts aggregated over the last five (four and a bit...) NHL regular seasons, updated to include the bit that was the 2013 bit of a season.

Analyses of individual seasons (including explanations of the CHIP figures and their limitations) plus my previous aggregate analysis (aggreganalysis?) are at the following links:

2013 
4-year analysis (2008/09 - 2011/12)

 Is there a correlation between injuries and a team's performance?

This is a plot of standings points per game against CHIP per game for each team over the last five seasons (click to enlarge):

 

By no means a comprehensive or detailed analysis - I suspect there are more than a few confounding variables creating a lot of noise - but this does at least suggest the correlation might not be as strong as you might initially expect (the R-squared coefficient is only 0.057, for what it's worth).

Do injuries increase with age?

Again, a reasonably crude measure, but the following chart shows total man-games lost to injury/illness over the last five seasons, distributed by the age of the player (as at the 1 January during each season - or before the 2013 season), plus the total number of games played by all players.

I've not attempted to make any adjustment for the fact that some of the games missed are attributable to season-long or career-ending absences, or that the games played number for goalies doesn't reflect the number of games they were available and dressed for.


A fairly useful illustration of the age profile of the NHL player population and the distribution of injury absences, but to make this a bit clearer, the next chart shows the crude proportion of games missed by each age cohort, expressed as MGL / (MGL + GP):


Sample sizes get pretty sketchy below age 20 and towards the late-30s, unsurprisingly, but enough here I think to support the ultra-controversial hypothesis that old people get stashed on LTIR by the Flyers when not wanted hurt more for longer.

Part II may well include another big fat grid of MGL and CHIP numbers by team and division over the five-year period, perhaps including an adjustment for distorting season-long absences.  Hold your breath.