RealGM

count55 wrote:With the advent of easy access to computers, fantasy sports, and the internet, there has been an explosion in not only the amount of statistics available, but the sheer number of metrics used to measure the performance of athletes and teams across all sports. It's even reached the point where statistical modeling is used not just as a tool of sports management, but in some cases, as the primary decision-making tool/driver of professional franchises.

I thought it'd be interesting to open a discussion about the value of this turn of events. However, rather than starting an esoteric discussion on the broad nature of the subject, I thought we'd go through different metrics. The idea being that we understand what the metric is, and how it is used. Then we can discuss how valid we think it is, how it should be used, whether it's being used correctly, and how relevant it is to the way we think.

Considering that this is a forum where disagreements arise regularly, maybe it would help for us to come to some conclusions and understanding about the stats we may or should (or shouldn't) use to support our positions.

The Definition/Overview wrote:The Player Efficiency Rating (PER) is a rating of a player's per-minute productivity.

To generate it, I created formulas -- which I outlined in tortuous detail in the book "Pro Basketball Forecast" -- that return a value for each of a player's accomplishments. That includes positive accomplishments, such as field goals, free throws, 3-pointers, assists, rebounds, blocks and steals, and negative ones, such as missed shots, turnovers and personal fouls.

Two important things to remember about PER is that it's per-minute and pace-adjusted.

It's a per-minute measure because that allows us to compare, say, T.J. Ford to Jose Calderon, even though there is a disparity in the minutes they played.

I also adjust each player's rating for his team's pace, so that players on a slow-paced team like Detroit aren't penalized just because their team's games have fewer possessions than those of a fast-paced team such as Golden State.

Bear in mind that this rating is not the final, once-and-for-all answer for a player's accomplishments during the season. This is especially true for players -- such as Bruce Bowen and Jason Collins -- who are defensive specialists but don't get many blocks or steals.

What PER can do, however, is summarize a player's statistical accomplishments in a single number. That allows us to unify the disparate data on each player that we try to track in our heads (e.g., Corey Maggette: free-throw machine, good rebounder, decent shooter, poor passer, etc.) so that we can move on to evaluating what might be missing from the stats.

I set the league average in PER to 15.00 every season.

Among players who played at least 500 minutes in 2006-07, the highest rating was Dwyane Wade's 29.04. The lowest was Collins's 3.02.