NBA 
Is the NBA box score incomplete?
The statistical revolution has changed basketball considerably, raising new questions about what constitutes effective play and whether or not certain stats have been overlooked or overemphasized over the course of NBA history. One of the chief goals of the movement has been to quantify the efforts of role players whose stats "don't show up in the box score." These players are the screeners, defenders, and effort guys who fight for loose balls and generally do the little things that hold a team together.
However, there's some question as to how that can be done, especially given that some contributions are more easily identifiable in qualitative terms than quantifiable numbers. It's hard to tally good defensive rotations, or even to agree on a definition. And how do you explain the offensive role of a screener in stats?
These questions are difficult to answer, but they deserve suggestions and extended thought. At HoopSpeak, Brett Koremenos suggests one possible change to support and reward these players — adding screens to the box score:
It’s not that only selfish players need something measurable to improve the subtle areas of their games. One of the high school players I work with, who is a great kid, teammate and worker in every respect, still recaps his contribution to games with me by focusing on how many points he scored. And why shouldn’t he? Scoring points is what his coach asks him to do, the reason why his family/friends praise him after games and the draw for Division I college coaches to come recruit him. [...]
In the ugly, amoral meat-grinder that is the basketball industry, players — even low D1 prospects like that high school player — are also increasingly coming up as brands. At first they are marketed to college programs by AAU coaches and should they excel at that stage, they are then pitched to NBA front offices by agents. The best way to sell a brand is to hit on indicators — points, rebounds and assists — that link the player to thriving NBA player brands. Simply adding a screening stat won’t immediately fix all of this, but it would quantify an important act that coaches pull their hair out trying to get their players to accomplish.
You can’t improve what you don’t measure. The formation of such a stat shows emphasis, that players are getting noticed — and possibly even praised — for doing it. And with the way NBA trends filter down to the lower ranks, there is a chance that more kids come out taking pride in their screening ability. All because the box score finally gives them a reason to do so.
Rob Mahoney, another smart man, saw the value in this idea and added some thoughts at The Point Forward:
The process of actually deriving screen-related stats would bring its own challenges, and measuring the wrong kinds of screens might only reinforce bad habits among players in the same way that measuring points encourages some to be unapologetic gunners. The elements of screening that matter most would have to be pinpointed if any screening stat were to be adopted into the box score on any level, and of course the relevant bodies (the NBA, NCAA, etc.) would need to see the virtues of that stat’s inclusion. It would be a long, arduous process with a superficially minute payoff, and it’s likely that the impact of screen tracking wouldn’t even be detectable for some time.
Both Brett and Rob put their observations in terms of what it means for players, and that's a useful way to think of the effects of changing the box score as they apply to what happens on the court. However, players have other feedback loops for assessing their performance. While these external factors certainly play an important role in developing habits, a coach can still tel a player whether or not what he's doing contributes to the team achieving its goals. To use an NBA example, a coach (or any intelligent observer) can communicate what makes Omer Asik an essential member of the Houston Rockets even though his screens and defense don't get listed in a box score. If they were, they would serve to emphasize his play, but they're not totally necessary to understanding why he's important.
Yet the box score is absolutely fundamental to explaining a basketball game to someone who couldn't watch it. If I have to miss an important or interesting game in the pursuit of a well-rounded life, my first method of catching up is always to read the box score. While efficiency stats like points per 100 possessions and PER can explain which players are most effective, a box score, with its raw tabulations of numbers, does a better job of explaining what a game looked like — who took the most shots, who grabbed rebounds, who didn't get the ball very much, etc.
In other words, the box score expresses the form of basketball. For people who don't get to watch every game or zero in on the habits of every player in the league, it's a useful shorthand for communicating contributions. For me, it's primarily effective as a tool for fans who want to stay abreast of the night-to-night events of the league but can't devote unlimited time to doing so. They provide a shorthand guide to the sport.
The good news is that, even by this different view, tabulating screens is still very important to expressing what happened in a game. In current box scores, there's no way to express what these players do in a possession — if box scores show only who has the ball, then it's possible to imagine these players standing off to the side while various one-on-one battles play out. (I don't think it's a coincidence that people who don't watch much of the NBA think the offenses aren't team-oriented.) Putting screens in the box score would better display the sheer amount of activity in an NBA possession, as well as give players in these roles their due. I'm all for highlighting quality play, but there can also be value in simple and accurate description of events.
