payitforward wrote:Davis averaged just over 29 minutes per game this year. Overall, his ball-possession stats vs. those of an average 4, indicate that during those minutes, our opponents have @5.3 more opportunities to score relative to the Wizards than they would if an NBA average 4 (i.e. with average ball possession numbers: rebounds, steals, TOs, blocks & fouls) played those minutes.
I've never been a fan of this analysis. First off, I assume you're pulling this from BoxScoreGeeks? If so, I can't quite replicate it. Assuming you're looking at the difference between Bertans's 2019-2020 averages and those of an "average" player at his position, I count him being down five rebounds, "up" 0.8 turnovers (i.e. committing 0.8 fewer than average), down 0.6 blocks, down 0.2 steals, and "up" 0.4 fouls per 48 (or is it 40?). That is, your method would have him allowing (5 - 0.8 + 0.6 + 0.2 - 0.4 = 4.6) additional scoring opportunities. Doing the same exercise with his career averages gets a bit closer to the 5.3 number you arrived at, although all of these numbers would need to be adjusted (downwards) to match the 29 minutes/game figure that you mentioned. (It's strongly possible that either you or I just missed a category, though, so let me know if my guess at your methodology is off.)
I don't think it's that clean a calculation, though. For one, and I've made this point a bunch of times already, but the failure of Bertans alone to secure a rebound on either end is not automatically a scoring opportunity (i.e. possession) for the other team. The failure of any Wizards player
to grab the board is. The relevant statistic here is team TRB%, and the effect that Bertans's presence has on it. I agree, of course, that for Bertans it's probably negative relative to the average 4 (although it should be noted that BSG compares his numbers to the average "big," which I assume is a composite of 4s and the generally even better-rebounding 5s), but at this point it's hard to separate out his specific rebounding numbers, affected as they are by the fact that he spends most of his offensive possessions damn near half-court, from the larger strategic question of balancing the effect his spacing has on the rest of the team's offensive performance against the improved rebounding but reduced spacing that a larger, more range-limited "traditional" PF might offer. As you may notice, this corresponds to exactly the two factors you mentioned: the ability to maximize the value of shots the team takes, vs. the ability to maximize the number of offensive possessions by way of additional rebounding power. It also suggests that one way of estimating Bertans's value would be to look at the overall supply (and contract value) of players who have a similar impact on their teams offensive production, or
who provide a similar level of impact on a team's ORB% and/or DRB%.
Turnovers and steals, pretty straightforward. Fouls and blocks, though, also present issues. The first is that all fouls aren't created equal - offensive fouls result in a change of possession (and, accordingly, are already credited to the player as a turnover!), but defensive fouls do not. (Some number of defensive fouls do result in valuable free throw opportunities, but there's no way that I'm aware of to separate the resultant effect on opponent offense out from the data.) If I were to guess, I'd suspect that Bertans's distribution of fouls is even more defense-skewed than most because of his offensive role, but that's pure speculation. As for blocks, they are by no means guaranteed to be recovered by the defense. (In fact, the defense is actually much more likely to get a rebound of a missed shot than they are recover one that is blocked: http://www.82games.com/comm16.htm
). In sum, I'm not sure that the simple addition/subtraction approach is appropriate for these either.
Since this conversation had me looking at NBA WOWY once more, here are some other interesting numbers dealing with team scoring opportunities/use of possessions with Bertans on and off the court:
Bertans was on the court for 3463 Wizards possessions, which resulted in 3008 shots (86.9%
). Team TS% on those shots was 58.8%
. During the opponent's 3463 possessions*
in that time, they took 2953 shots (85.3%
). Opponent TS% on those shots was 59.4%
Bertans was off the court for 3205 Wizards possessions, which resulted in 2813 shots (87.8%
). Team TS% on those shots was 54.5%
. During the opponent's 3205 possessions in that time, they took 2719 shots (84.8%
). Opponent TS% on those shots was 60.1%
Thus, Bertans's implied impact on the Wizards team offensive volume and efficiency is to slightly reduce the number of scoring opportunities, but greatly increase the value of the shots that are taken (0.9% fewer shots to possessions, 4.3% higher TS%). His effect on the Wizards team defensive volume and efficiency is to slightly increase the number of scoring opportunities, but slightly reduce the value of the shots that are taken (0.5% more shots to possessions, 0.7% lower TS%).
There's no question that Bertans's contributions come primarily on offense, but by your two-factor system his measurable impact on the team is quite clearly positive.
* Given that possession numbers for Wizards and opponents are identical, I'm assuming that offensive rebounds are being counted as extensions of the preceding possessions, rather than new possessions. Not ideal (imo), but since we're talking about scoring opportunities the important number here is the ratio of shots to possessions (i.e. the bolded percentages above).