Douglas A. Raeder

Paul M. Sommers

English

Research Papers in Economics

                                                                                                                                             
 
 
THE CAREER SAVE PERCENTAGE PROFILE 
OF NHL GOALIES 
 
 
by 
 
Paul M. Sommers 
And 
Douglas A. Raeder 
 
 
 
 
March  2010 
 
 
 
 
 
MIDDLEBURY COLLEGE ECONOMICS DISCUSSION PAPER NO. 10-17 
 
 
 
 
 
 
 
 
DEPARTMENT OF ECONOMICS 
MIDDLEBURY COLLEGE 
MIDDLEBURY, VERMONT 05753 
 
http://www.middlebury.edu/~econ 
 
 
 
 
 
                                                                                                                                             2 
 
 
 
 
 
 
 
 
THE CAREER SAVE PERCENTAGE PROFILE 
OF NHL GOALIES 
 
 
 
by 
 
 
 
 
Douglas A. Raeder 
Paul M. Sommers 
 
 
 
 
 
 
 
Department of Economics 
Middlebury College 
Middlebury, Vermont 05753 
psommers@middlebury.edu                                                                                                                                             3 
 
 
 
THE CAREER SAVE PERCENTAGE PROFILE 
OF NHL GOALIES 
 
 
 
 
  For most professional athletes, productivity increases rather quickly, tops off, and then 
declines as skills diminish or health declines with age.  Career length and the point where 
productivity “tops off” varies with one’s sport.  And, even within a given sport, the point where 
one reaches his or her prime may not be well-defined. 
  In this brief note, we endeavor to show how a representative goalie’s save percentage 
varies with years in the National Hockey League (NHL).  To do this, we will regress the save 
percentage
1,2 of a goalie in the NHL against his career save percentage (through the 2008-09 
season), years in the NHL, and years squared for all 75 goalies who played a minimum of five 
games in 2008-09.  These seventy-five goalies had a combined total of 373 years of playing 
experience.
3  For a goalie (like Chris Osgood of the Detroit Red Wings) with, say, 15 years of 
playing experience (as of 2008-09), there would be 15 observations (of the 373 total) for that 
particular player.  For a goalie with a given career save percentage, we should be able to show 
that the season-to-season save percentage rises at a diminishing rate for several seasons and 
reaches a peak.  Thereafter, the save percentage declines.  Of particular interest is the point where 
the performance profile peaks for an NHL goalie. 
 
The Model 
  A goalie’s save percentage in year t  [ SVPt ] for each of his n years in the NHL (with a 
minimum of ten games played per season before 2008-09) was regressed against career year 
(which for a representative goalie varies from 1 to n) [ Yeart ], career years squared [
2
t Year ], and 
his lifetime or career save percentage [ Lifetime_SVP ] through the 2008-09 season, as follows:                                                                                                                                             4 
 
 
 
(1)               SVPt  =  0 β   +   1 β  Yeart   +   2 β  
2
t Year   +   3 β  Lifetime_SVP  +    t ε   
 
 
where  t ε  denotes a stochastic disturbance (or error) term which may take on positive or negative 
values.  If a goalie’s save percentage rises with career year and then falls after a point, then b1, the 
least squares estimate for 1 β , should be positive and b2, the least squares estimate for  2 β , should 
be negative.
4  The peak point is found by taking the partial derivative of SVPt with respect to 
Yeart , setting this derivative equal to zero, and solving for Yeart in terms of b1 and b2.  That is, 
 
(2)                                                  =
∂
∂
t
t
Year
SVP
 b1  +  b2 Yeart  =  0 
 
 
or  Year
*  =  – b1 / 2b2 , where  Year
*  denotes the career year where save percentage peaks.  All 
performance data are from www.nhl.com . 
 
 
The Results 
 
  The 2008-09 regression equation is as follows (t-values in parentheses): 
 
(3)         SVPt  =  – 0.057  +  .0009212 Yeart  –  .000077 
2
t Year   +  1.059 Lifetime_SVP 
                             (-0.80)        (1.83)                    (-2.15)                 (13.51) 
 
                                                                                                                                    
2 R   = .345 
 
 
For this regression, Year
* = 5.98, that is, the point in a goalie’s career where the save percentage 
peaks.  Figure 1 shows the profile of a goalie whose career save percentage was equal to the 
average of the seventy-five goalies in the sample (.904).                                                                                                                                             5 
 
 
Concluding Remarks 
  The save percentage profile of a representative NHL goalie is derived for all goalies in 
2008-09.  The profile typically rises, at least up to a point, and then falls (sometime around their 
sixth year in the league). 
  Interested readers might be curious to see how this profile has changed (if at all) from one 
decade to the next.  Are goalies peaking later in their career than did their counterparts one or two 
decades earlier?  If NHL goalies now benefit more than their predecessors from off-season 
training and better conditioning, not to mention the improvements in sports medicine and physical 
therapy, are performance profiles now flatter or higher beyond the peak point than they used to be?                                                                                                                                             6 
 
 
Figure 1. 
 
Year
S
a
v
e
 
P
e
r
c
e
n
t
a
g
e
14 12 10 8 6 4 2 0
0.904
0.903
0.902
0.901
0.900
Career Save Percentage Profile of an Average Starting NHL Goalie
                                                                                                                                             7 
 
 
 
Footnotes 
 
1.  A goalie’s save percentage is found by dividing the number of saves (i.e., the number of 
  shots on goal a goaltender stops) by the total number of shots on goal.  A 90 percent save 
  percentage is here expressed as .900. 
 
2.  Goals against average (another common measure of a goalie’s performance) is more 
  heavily influenced by his teammates’ defensive efforts.  Save percentage is regarded to 
  be a better measure of the goalie’s own performance in net. 
 
3.  In seasons prior to 2008-09, we required the goalie to play a minimum of ten games  
  for the season to count as a “year of playing experience.” 
 
4.  The coefficient on Lifetime_SVP should be close to 1.0.  The estimated coefficient b3 
  could be greater than 1.0 since seasons with fewer than 10 games played (usually in a  
  rookie’s first year or two in the NHL with typically little ice time) can result in  
  uncharacteristically good save percentages and hence raise the goalie’s lifetime save 
  percentage.      
 
 
 
 

The Career Save Percentage Profile of NHL Goalies

http://www.middlebury.edu/services/econ/repec/mdl/ancoec/1017.pdf

The Career Save Percentage Profile of NHL Goalies

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