Friday, December 01, 2006

Alan Ryder on NHL "Offensive Engagement"

Last season, it seemed like Dean McAmmond's linemates couldn't get anything done without him. McAmmond got a point on 88% of the even-strength goals the Blues scored when he was on the ice.

Chris Campoli was the Dean McAmmond of defensemen. Campoli led the league in this category among blueliners by scoring or assisting on 52% of his plus-minus "plusses".

These figures are from
Alan Ryder's latest article on Ryder believes that players who excel in this category, which he calls "offensive engagement" (OE), are showing themselves to be capable of playing higher in the depth chart than they already play. Of course, many players high in this category (Jagr at 85%, Sundin at 80%) are already treated like star players. But Ryder argues that guys like McAmmond show themselves to be better than their point totals indicate – "close your eyes and imagine an eagle trying to soar with the turkeys."

Seems logical, but there's probably a fair bit of random luck in the stats too. Campoli's league high OE is based on 21 points out of 40 plusses. If the league average for defensemen is 35% (I'm guessing here because Ryder doesn't tell us), Campoli is only 7 points above average. That's 2.3 standard deviations, significant for a randomly-chosen player but perhaps just random for the league leader.

In any case, it shouldn't be too hard to do a study to check if players high in OE tend to show improvement in the future.

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At Saturday, December 02, 2006 1:59:00 PM, Blogger JavaGeek said...

The funny thing is that you can technically get over 100% (you can get an assist w/o a plus.)

Testing distribution for randomness with known mean:
Using Prob. point given plus = 72% forwards
And Prob. point given plus = 37% defense
- calculated using actual data.

This just counts how many events are Z>n standard deviations away and compares to expected value (in brackets).

Z>2.50: 1/296 = 0.3% (0.6%)
Z>2.25: 2/296 = 0.6% (1.2%)
Z>2.00: 6/296 = 2.0% (2.3%)
Z>1.75: 12/296 = 4.1% (4.0%)

In fact one can tell whether a player is overrated using these figures (got more points than random expectation). It's strange, but it appears McAmmond is aiming to make that list two years in a row...

At Saturday, December 02, 2006 4:16:00 PM, Anonymous Anonymous said...

The thing is though that McAmmond doesn't play with very talented players most of the time. All this stat really tells you is whether he is the most offensive minded player on the ice when he is on the ice. But if someone is playing with a couple of AHL scrubs, this isn't necessarily hard to do. But that doesn't make you a good player.

At Monday, December 04, 2006 10:25:00 AM, Blogger Don Coffin said...

" shouldn't be too hard to do a study to check if players high in OE tend to show improvement in the future."

Even easier to see if this persists over time--what's the year-to-year correlation?


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