Forwarded per request.
 
>Date: Sun, 19 Feb 1995 05:00:05 -0500
>From: [log in to unmask] (John Edwards)
>To: [log in to unmask]
>Subject: Re: Goalie Perseverance (HE)
>Reply-To: [log in to unmask]
>X-UIDL: 793227347.008
>
>>>As I said above, I've never seen Herlofsky play, so I can't pass final
>>>judgement on him. I can, however, tell you why his Perserverence Rating
>>>is so low. Basically, while he has a great GAA (3.14), his save% is very
>>>ordinary (84.72%). All the other goaltenders mentioned in the top 9 have
>>>save% from 87-90%. He also faces an average of only 20 shots per game,
>>>while most of the others listed are facing 29-33 shots per game.
>>
>>So goalies with very good team defense in front of them who face fewer shots
>>per game automatically suffer using this "Perserverence Rating".  Is that
fair?
>
>Well, the rating is designed to measure a goaltender's perserverance under
>pressure.
>
>A goaltender who faces fewer shots per game will not automatically
>suffer. Blair Allison of Maine is only seeing 23 shots per game, but his
>Perseverence Rating is 930.96.
>
>>Again, as Mike Machnik asked, where did the "rating" come from?  How was the
>>range of great to horrible decided?  What else was this "rating" measured
>>against?
>
>The rating was developed by Jeff Klein and Karl-Eric Reif. It was published
>in their book "The Klein and Reif Hockey Compendium" (McClelland and Stewart,
>1987). This statistic is explained fully in Chapter 8 of the book. The main
>rationale for this new statistic is that save percentage does nothing to
>measure a goaltender's workload. The assumption, I guess, is that a goalie
>who only faces 20 shots per game has an easier time of it than one who faces
>40. It was developed based on NHL statistics from the early-to-mid 80s.
>The ranges of what is good, and what isn't were developed, I would assume,
>based on those. They may vary in the NC$$, but I don't think they vary all
>that much. 881.44 is still pretty bad.
>
>>Is it fair that BU's goalies suffer because they have good team
>>defense in front of them (most games)?  BU has allowed an average of only 23
>>shots per game, while they average taking 37 shots per game, so according to
>>this rating they are bad goalies despits having good GAA's, average saves
>>percentages and winning records.
>
>First, it is impossible to completely divorce a goaltender's performance from
>that of his team, but I think this comes as close as I've seen to doing that.
>
>>I did quick calculations for Tom Noble and Derek yesterday and I came up
>>with a 905 overall rating for Derek ("very poor") and 918 for Tom ("poor"),
>>and a 912 for BU gaoltending overall ("poor").  Then I did the calculations
>>changing only the shots per game (i.e., the saves percentage remains the
>>same).  If Tom and Derek faced an average of 37 shots per game instead of
>>the 24 (Tom) and 22 (Derek) they do face guess what?  Tom becomes becomes
>>"very good" (940) and Derek becomes "good" (931).
>>
>>I think that a supposed goalie rating that can change so much based on a
>>factor beyond the goalie's ability to control (shots per game faced) is a
>>very unfair and unreliable.
>
>But two paragraphs ago you were saying that Herlofsky and Noble were good
>because they had good win-loss records and good GAAs. There is no goalie
>stat that is more out of his control than win-loss record. Herlofsky's
>GAA is also a function of his defence. Since he's only seeing 20 shots
>per game, I would be worried if his GAA were much more than 3.14.
>
>Just for fun, I did some number-playing as well. It turns out that if
>Herlofsky's save% were 0.8862 (the average of the other 8 HE goalies),
>his Perseverence Rating would go up to 920.52. That part of it is within
>his control.
>
>>By the way, I am one of the first to admit that Derek is having a bad year
>>this season.  He has allowed far too many goals and he has a depressing low
>>saves percentage, but he still have a good GAA and was won 11 games so far.
>>He has also been quoted that he likes to face at least 30 shots per game to
>>stay sharp, but he has faced an average of only 22 shots per game this season.
>
>And I really didn't intend to end up dumping on BU goalies. I have nothing
>to do with Maine, honest. :-)
>
>But it does look to me that Herlofsky is overrated, at least this year.
>I would be interested in seeing his stats for last year. If I find them
>in the archives, I'll try to figure out his P.R. for last year.
>
>See you later,
>John
>
>--
>John C.K. Edwards        Stats Geek, Ottawa Jr Senators (23-22-3 51pts) (CJHL)
>Carleton U., Law IV                   I don't give a damn about being liked,
>[log in to unmask]           but I sure as hell intend to be respected.
>All Canadian [Tier II] Junior A standings: http://chat.carleton.ca/~jedwards
>
>