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08-09-2012, 04:06 PM
  #36
Czech Your Math
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I think the metric has quite a bit of predictability on a team level. It's not just the top two teams, but other teams that either have systems designed to prevent high quality shots or teams that are just not very good. Sure if you take the middle group of teams, they will tend to regress to the mean, as they would in many other metrics of overall value, because they tend to be average.

When I look at the featured examples that are supposed to illustrate the metric most clearly on a team level, 2012 Minnesota and 2011 San Jose, I immediately looked at the most likely culprits (goaltending in both cases, offense in Minnesota's case, etc.) and these explained the change in the fortune of each team much more than this metric. If the biggest examples of teams regressing are so obviously flawed, that doesn't give me much faith in the metric on a team level. Give me the PDO data for the past few years for all teams and I would guess I could predict who the top and bottom teams would be next year with decent accuracy. This isn't what would be expected from the metric.

It wasn't just Vancouver and Boston, but teams like Phoenix, Rangers and Nashville. Their overall PDOs may have been generally lower or higher for a shorter time, but there's a clear correlation to some degree. The Islanders, Columbus, and Toronto didn't have one overall PDO of 1000 or higher in 5 years between them. That's no coincidence.

I can see some use on an individual level, but it seems overblown. I mean, if a superstar is having a rough patch, most of us understand it's just bad luck and don't need to check their PDO to tell us this. If a scrub goes on a tear, it's usually not sustainable, and we intuitively know this, we don't need to consult PDO. As TDMM said, it's best not to rely on raw plus-minus for a single season or a partial season, and anyone worth their salt knows this. It doesn't mean raw plus-minus is useless, and maybe PDO isn't either, but that also doesn't automatically make either particularly useful.

Remember, this stat was touted as the "single most useful stat in hockey" and described as "primarily driven by luck." By disproving the latter, along with the featured examples, it becomes evident that the former statement is pure hyperbole.


Last edited by Czech Your Math: 08-09-2012 at 05:03 PM.
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