Based upon the few years of observation and the statistical work of others, I've came up with the following logic for evaluating rookie performance last year.
Rookie Rankings: A Resolution for the ROY Debate - Swish Appeal
The best rookies can create their own scoring opportunities – and do so efficiently – while contributing to a team’s success.
As such, I’ve used a combination of three statistics – usage rate (the rate at which a player creates plays for themselves), Chaiken efficiency ratio (the ratio of scoring plays a player is individually responsible for vs. turnovers and missed shots), and Boxscores (a player’s individual to team wins).
A few small changes:
- Consistent with what I worked out earlier this season when looking at team chemistry, I've used Chaiken efficiency ratio (or points/empty possession) for high usage players and floor percentage for low usage players. The logic for that is explained there.
- Boxscores is actually a little unfair to use for rookies. First, every rookie is on a different developmental trajectory so their contribution to team wins over the course of a season can be somewhat erratic. In the ideal scenario, one might assume that a rookie's ability to contribute to a team's success would slowly increase over the course of a season. Second, for the average rookie, other players -- sometimes 6-7 -- deserve far more credit for the team's wins. Third, to a minor extent, there are situations where a bad rookie on a good team could benefit more than a good rookie on a bad team from a metric so closely tied to team wins.
So given that the developmental trajectory, expected contribution, and minutes for rookies will vary widely -- sometimes independent of the actual talent they've demonstrated on the court -- a metric that measures their demonstrated ability in whatever time they got on the floor might be more helpful. Marginal Victories Produced is a good way to figure out how big a role a player plays in a rotation, but for demonstrated ability, I use another Sparks creation Valuable Contributions Ratio.
The Arbitrarian: Individual Contributions To Team Success | Hardwood Paroxysm
Another useful measure, especially for comparing players on poor teams, or those who played limited minutes, is what I call the Valuable Contributions Ratio (VCR). This is a pace- and playing time- adjusted metric of productivity assessed at the per-minute level. As above, this calculation is straightforward and intuitive. Merely take each player’s PVC (MEV/team MEV) and divide it by each player’s percent of team minutes played (min/team min). Thus, we are dividing a percentage by another percentage (which is why I call it a ratio–units are somewhat meaningless). This statistic controls for team pace and playing time, and is independent of team quality–it captures productivity relative to the time allowed for production.
This is useful for comparing bench players, players who miss a substantial number of games, and rookies. Bench players get a "fair shake" by this statistic, because they often have less time on the floor in which to accumulate MEV toward a larger cumulative share of team success...VCR is useful for comparing rookies, as well, since they often play relatively few minutes, and since their teams often win very few games. Rookies with high BXS are the most impressive, but more often than not, rookies don’t produce many wins. Rather, they may produce MEV efficiently, and we can see this in VCR.
Click here for even more about how VCR can be applied to basketball.
- Last, but along those lines, is another problem even with VCR and it is epitomized by a player like Shalee Lehning. Scoring is still important in basketball -- hence the reason why usage and efficiency seems to be so valuable in evaluating rookies -- and even a metric like VCR weights a player's ability to put points on the board heavily. However, the problem is that a rookie might not come on the floor and get a whole lot of shots. During that time, they might do other things very well that speak to value beyond just scoring. For that, we can use another metric called "value added", with a caveat.
Hardwood Paroxysm " Blog Archive " The Arbitrarian: Marginal productivity of box score statistics
"Value Added," to see each player’s MEV less points scored, per game. This is an estimate of the non-scoring ways in which each individual helps his team and hurts the other team. Pass-first point guards, defensive-minded bangers, and well-rounded contributors rise to the top. Chuckers (see: Ben Gordon), often characterized by flashy scoring numbers, sink to the bottom. These players still contribute positively, through their ability to score, but their positive value is diminished by the number of shots they miss, turnovers they give up, and the other things they fail to do to help their team improve that final margin.
- After those things, 2 point percentage also seems to be an important determinant of success, in addition to assist rate for guards.