mopper8 wrote:mopper, how much do you think Thurmond improved their defensive efficiency rel to lg average ? how many points ?
[Alonzo Mourning comparison...]
In that scenario, you have Thurmond's contributions making the team Drtg a total of
1.9 points lower,
22% of the team's overall improvement.
I think that's probably reasonable to expect from a defensively-gifted rookie who's playing ~26 mpg. That sounds right to me. So, there you have it--my best guess would be that he improved their Drtg by ~2 points out of the overall 8.5 improvement.
This is really interesting, and as is the case in this project, sometimes it's worth stepping back from the specifics and address broader concepts.
In this case, Wilt Chamberlain has me thinking about the difference in per possession impact between players logging 44-48 mpg versus 35-40 mpg. When players like Steve Nash, who posted a +17.6/100 in 2005 on offense, have a large impact on the game in less time played,
they will have a smaller overall impact on their team's results. (Hello, Nate Thurmond, 1964) However, of course, the impact they are having per possession is greater. In Nash's case, he played 34.3 mpg in 2005 and missed 7 whole games...so he played 65% of his team's total minutes. That means:
65% of minutes at 121.7
35% of minutes at 104.1
which should dictate a 115.5 team ORtg (actual ORtg on B-R is 114.5).
Someone like Chamberlain falls on the opposite end of the spectrum. He's typically playing the entire game, so his impact is distributed across the entire game.
So what's the point vis a vis Wilt and Thurmond?
In Thurmond's case, we could attempt to estimate how much overall impact he had at his defensive peak (67-73?) and then, at the max, take the % of minutes he played in 1964 relative to his peak years to determine his overall team defensive impact. Mopper did something like this quite well. But it's possible Thurmond's defensive impact is greater than Mourning's due to era differences. So here's how I go about estimating something like this:
Start with the Warriors DRtg's and the % of minutes Thurmond played starting post-Wilt:
1966 94.2 (0.6) 75.2%
1967 92.9 (3.2) 70.5% *Sharman
1968 94.2 (2.8) 56.1% *Sharman
1969 92.9 (2.7) 80.6%
1970 98.3 (1.2) 48.4%
1971 95.3 (1.2) 85.0% *Attles 71-74
1972 94.8 (3.5) 85.3%
1973 93.9 (3.1) 86.6%
1974 98.4 (-0.7) 62.5%
A few things: the Warriors had a lot of pretty solid defensive teams. Was Clyde Lee also a decent defender (67-74)? I've seen a few old articles that praise his defensive effort. Jerry Lucas -- not an impact defender by reputation -- was there in 70 and 71. Rudy LaRusso 68 and 69 (all-defensive team in 1969 but never someone I thought of as an elite defender). Attles 75 team was fantastic defensively using swarming/trapping guards with Cliff Ray and George Johnson behind.
We know Thurmond's +/- from his missed games looks huge in 1967 (defensive difference of 8.8 ppg). They played 129 possessions/game which means if the pace held constant with/without Thurmond in 1967 the DRtg difference was
6.8/100 (which would give Nate a defensive on/off of 7.5 that year. But even that wouldn't be an absolute measure, but a conditional one; When Nate Thurmond wasn't on the floor, the 1967 Warriors really suffered defensively. The 1964 team probably would have less of a drop with Wilt Chamberlain staying on the court.
The 68 team had changes from the 67 team, despite the same coach. But then there's 69 to 71 to consider. Add guard Ron Williams. Add Lucas. Remove LaRusso. Bring in Attles.
Next, what if we assumed it's only Thurmond's performance that pulls his teams up from average? Then his impact would be (DRtg/MP):
Trying to fit the numbers closer to Thurmond's 1967 estimate, let's assume all of his team's are consistently an estimated -1.0 without him on defense, as was the case in 1967. Then Thurmond's individual defensive impact per year is:
1966 2.1
1967 6.0
1968 6.8
1969 4.6
1970 4.6
1971 2.6
1972 5.3
1973 4.7
1974 0.5
Only I think that the difference in performance there in certain years like 1966, 1969 (1st team All-D) and 1971 (1st team All-D) are way too large to just be variance from Thurmond or even the team. So other factors must be involved, which should be obvious because we don't see incredible roster/team consistency from 69 to 71.
I tend to think of a defensive anchor's impact being fairly consistent as long as he remains healthy and his effort/coaching is similar. Which means either Thurmond had really bad defensive efforts in 1966 and 1971 (unlikely), or the fluctuation in those numbers has to do with the team around him. In 1967, Clyde Lee joined the team and Bill Sharman took over as coach as well as a few other rotational changes. This can be seen quite clearly if we invert the numbers and assume it's Thurmond's defensive impact as the anchor that is remaining constant. Then his team's defensive ratings without him would be:
1966 -6.5
1967 -3.6
1968 -2.5
1969 -4.5
1970 -3.1
1971 -6.1
1972 -3.8
1973 -4.2
1974 -5.8
So what happened from 1970 to 1971? Did Attles make that big of a difference? Can a team's variance just be that large (I've never run standard dev numbers on something like this to have an idea.) Was it actually Thurmond's play that suffered in 1970 because of injury? Perhaps some combination of that. At some point, something has to give. For instance, why weren't his teams worse in 68 and 70 when he missed so much time?
Clearly, it's a fuzzy operation. And both of the last two numerical exercises are overly simplified as it is.
So in making a guess, let's give peak Thurmond something comparable to that 1967 estimate, say ~7 on/off, which, in my mind, is an incredibly generous estimate. That means that if he had that same impact in 1964, playing 50.9% of his team's minutes, he would alter the team DRtg by 3.5 pts/100. At something like ~5 on/off, it's about 2.5 pts/100. And again, that's assuming that he played at levels comparable to his peak play.
In conclusion, there is no way I'm giving mentally crediting Nate Thurmond for more than 3 pts/100 of that change, and probably crediting him with on order of 2 pts/100 for that team's defensive change. In other words, somewhere between 25-35% of the credit could plausibly go to Thurmond, even at those minutes played. And I think Chamberlain deserves the majority of the remaining share.
PS That means in 1963, Wilt's impact on the defensive side of the ball is...er...weak. To put it nicely.
