Using the play-by-play data provided by Ryan Parker over at Basketball Geek, there's a lot we can uncover about the Rockets. I wanted to use this thread to just post whatever interesting things (interesting to me, anyway) I happen to find. The first topic I wanted to look into was how the Rockets offense impacts their defense, and vice versa. What do I mean by that? Well, usually we think of offense and defense as separate. But in actuality there is a relationship between the two. If you get a defensive stop, you should be able to increase your likelihood of scoring on your ensuing possession. Likewise, if your offense sputters and you miss a shot or turn the ball over, that'll help feed into the opposing team's offense. A lot of factors go into this. Are you a up-tempo, transition team? Then you're more likely to take advantage of your defensive stops. Are you an aggressive offensive rebounding team? Well, then you might make yourself vulnerable to other teams scoring against you. If you take a bad shot, or especially a quick, bad shot, that can kill your transition D going the other way. And of course who you have on the floor would also have an impact. As a preliminary study, I ran through every possession the Rockets played this season on offense and defense. I reasoned that the possession I'm interested in could have one of 5 outcomes: (1) Ended in a made free throw (due to a foul) (2) Ended in a missed free throw (3) Ended in a made field goal (4) Ended in a missed field goal (5) Ended in a turnover While a "defensive stop" is typically defined as holding an opponent to 0 points on a given possession, for my purposes here I'll treat as stop as a possession ending with either (4) or (5). Below, I've created tables that describes each possession (the rows), given the outcome of the prior possession (the columns). The first table is focusing on the Rockets offense, so the rows correspond to Rockets offensive possessions, while the columns are the their prior defensive possessions. And for the second table, we're looking at the outcome of the Rockets defensive possessions (the rows) given their prior offensive possession (the columns). Consider in the first table, the cell for row "MADE FG" and column "MADE FG". It reads 595/264. This means that there were 264 such possessions (a Rockets possession ending in a made field goal, following a defensive possession that ended in a made field goal). And over those 264 possessions, the Rockets scored a total of 595 points (or about 2.25 points per possession). Rockets on Offense: MADE FT MISSED FT MADE FG MISSED FG TURNOVER ------------------------------- --------------------- MISSED FT 4/4 0/1 16/17 17/15 7/8 MADE FT 51/23 10/4 132/65 95/50 57/27 MADE FG 161/74 29/13 595/264 499/222 291/136 ------------------------------- --------------------- MISSED FG 0/75 0/17 0/224 0/195 1/83 TURNOVER 0/25 0/7 0/126 0/80 0/59 ------------------------------- --------------------- 107.5 92.9 106.8 108.7 113.7 ------------------------------- --------------------- 106.3 110.5 On the second to last row on the Rockets Offense table, I summarize our offensive efficiency on possessions following each type of defensive possession. So, when a Rockets defensive possession ends in a made field goal for the other team, their offensive efficiency in the ensuing is 106.8. On the other hand, when the Rockets are able to create a turnover, their offensive efficiency jumps up to 113.7. Overall, the Rockets improve their offensive efficiency by about 4 points when they get a "stop". Now the defense ... Rockets on Defense: MADE FT MISSED FT MADE FG MISSED FG TURNOVER ------------------------------- --------------------- MISSED FT 8/6 0/0 12/13 12/13 4/5 MADE FT 29/15 2/1 142/66 141/76 63/31 MADE FG 144/67 39/19 508/236 479/221 268/126 ------------------------------- --------------------- MISSED FG 0/52 0/19 0/240 0/157 0/69 TURNOVER 0/30 0/6 1/123 0/94 0/53 ------------------------------- --------------------- 106.5 91.1 97.8 112.7 118.0 ------------------------------- --------------------- 99.1 114.4 This I found somewhat troubling. When the Rockets are able to get to the line or make a field goal, their defense in the ensuing possession is awesome -- holding opponents to a 99.1 defensive efficiency. But look at what happens when their possession ends in a missed field goal or a turnover. Their defensive efficiency is awful. Why the huge discrepency? Two things come to mind. First, the Rockets are crashing the offensive boards this year. That works out great when they get it. But when their scrappiness goes unrewarded, their transition defense is compromised. Perhaps this analysis is unfair to the Rockets, because they are very good at getting to those offensive boards (in a subsequent study, I could look at defensive efficiency after possessions on which the first shot attempt is a miss). The second reason is that with the Rockets looking to run more in transition, when their possession ends early that gives the opponent an opportunity to run right back on them. There is opportunity here as well for further examination of the play by play to see when exactly the Rockets are hurting themselves. Should they cut down those early 3-pointers, for instance? That's all for now. I welcome any comments.
Great analysis! The thing that pops out at me is the Rockets on Defense part. We're definetely crashing the boards more this year, and it's paying dividends with all those offensive rebounds. It probably does effect our transition D a bit because it takes a lot of energy to go for offensive boards.
I like the work you put in, great job! I wonder if there are conclusions to be drawn here outside "opponents score more off missed shots and turnovers than made shots". Naturally on missed shots/turnovers there is less court to cover for the offensive team to get to the basket which means less time for the D to get set, but how I am curious how much of it mental. I would also like to see the data with it just missed shots and not turnovers. Turnovers can skew a little because of breakaway dunks, etc.
I am sure this is the case with every single team in the league, what would be more interesting is if it was correlaled compared to the league average or vs other teams.
Brilliant breakdown on both offense and defense, thanks sir. Defensive efficiency really kills us when we crash the board more than ever and didn't get the boards, at the moment the trans D would be the most vulnerable no matter we got our defense set right away, it's gonna either be a bucket or a foul to send the opponent to line.
Basketball Geek has the play-by-play data for 72 of the 82 games last year. Good enough to make a comparison. Rockets on Offense (08/09): MADE FT MISSED FT MADE FG MISSED FG TURNOVER ------------------------------- --------------------- MADE FG 422/191 149/68 1967/872 1880/846 728/330 MISSED FT 12/16 6/6 59/57 40/33 22/23 MADE FT 130/66 26/12 537/269 425/224 182/93 ------------------------------- --------------------- MISSED FG 1/198 0/48 1/778 0/714 4/277 TURNOVER 0/111 0/24 0/380 0/346 0/126 ------------------------------- --------------------- 97.1 114.6 108.8 108.4 110.2 ------------------------------- --------------------- 106.9 108.9 Compared to last year, the Rockets are a little better at converting their "stops" into improved offense. Last year, per 100 possessions, their efficiency increase +2. This year, its +4. Rockets on Defense (08/09): MADE FT MISSED FT MADE FG MISSED FG TURNOVER ------------------------------- --------------------- MADE FG 551/253 106/49 1879/864 1632/743 951/444 MISSED FT 6/13 1/1 65/62 53/54 29/29 MADE FT 127/65 12/9 465/230 382/201 147/80 ------------------------------- --------------------- MISSED FG 0/263 0/52 0/859 1/681 1/308 TURNOVER 0/76 0/19 1/325 0/301 0/143 ------------------------------- --------------------- 102.1 91.5 103.0 104.4 112.4 ------------------------------- --------------------- 102.3 107.1 Here, we see that our defense improved by about 5 points per 100 possessions when we're able to score a field goal or get to the line. Allowing 107.1 efficiency when we're "stopped" doesn't look bad at all, compared to what we've done so far this year.
Your defense will always be superior after a made bucket than a missed one or a turnover. That is an axiom of basketball. The reason is three-fold. One, a made field goal requires the opposing team to inbound the ball. This requires a few seconds to first get the ball, walk out of bounds and then pass it back in. This allows the team that just made it's shot more time to back and get set on whatever defensive schema. A missed shot or turnover the ball is immediately in play - far less time. Second - a missed field goal and turnover results in the ball already being advance already closer to the opposing basket than an inbounds. There's less distance to cover. Third - the ball is most likely already advanced of at least one opposing defensive player. This results in 5-4, 4-3, 3-2, 2-1, 1-0 situations which are very high scoring. This is why turnovers are a double hit. Also, who misses the shot can make a difference. If a small guard gets past his man at the top of the key and then misses a layup which is rebounded by a big, that big can then pass to the guy who blew his assignment and the top of the key and he will be ahead of his defender who is still in the paint. Finally, another reason why shot-blockers are more valuable than just preventing a score.
Good stuff. A few thoughts: 1. In both years, the Rockets struggled on D after turning the ball over. Not a surprise, because pretty much every team struggles to one extent or another when turning the ball over. 2. The Rockets did quite a bit worse this year after TOs than they did last year. Here's my theory: a perimeter player turning the ball over is typically worse than a post player doing so. Last season, Yao Ming was by far the Rockets TO leader, followed by Artest, Brooks and Scola. This year, it goes Ariza, Brooks, Scola and Lowry. I am thinking that when Yao turns it over, the Rockets perimeter guys are more ready to play transition D, but when, say, Ariza turns it over, the transition D is mroe screwd. If he's penetrating, then the Rockets are one transition defender down. If he's hanging around the 3 point line, then there's not much defense behind him, either. 3. I think the most interesting thing what happens to Rockets D between Rockets missed FGs and the Rocket make FGs. You can see, roughly the benefit and cost of board crashing between the years: Benefit: Increase OReb% from .264 to .306 Cost: Decreased effectivness of transition D, where as Rockets lost 1.4 points per 100 possession on D (103 vs. 104.4) after missed shots compared to after made shots, now they lose a whopping 14.9 points (97.8 vs. 112.7) after missed shots compared to after makes. When I get a chance, I'd like to run some calculations as to whether it is "worth it" but will have to think some more. 4. The Rockets half-court D (i.e. D after "static situations" such as made baskets, made FTs and missed FTs) are actually better this season than it was last. Somewhat interstingly, after losing the slowest member of the team, and probably the last guy to get back on transition, it is their transiton D (after TOs and after missed shots) that is suffering. As discussed above, it seems likely that what's going on is that the Rockets are compensating for the loss of offensive talent by doing things that boost offense but hurts D. It's a tradeoff that I am guessing Morey's guys calculated to be worth it. Remember how basketball video games have this bar where you can decide how much you want to crash boards vs. get back on transition? The Rocket have moved the bar way over to the "crash boards" side. (They are also getting on fast breaks more, which is likely at the cost of defensive rebounds... but that is not reflected in these numbers here). In StarTrek terms, I am guessing what Captain Adelman does is called "diverting power from shields to disruptor." 5. The Rocket difference in defensive efficiency after made FTs and after made FGs this year has got to be a fluke.
great research. One name comes to my mind. JVG. Coach JVG is very against TO, that's why he didn't play that Greek pg. When the pg/ballhandler had TOs, it usually transfer to easy basket and generarte 'the momentum'. That's why rafer is a very good PG. He didn't make this kind of TOs and can forced TOs. That's why I don't like coach RA even though he's a great coach. 'Gun and run' can't win champaignship because they'll sacrifice defense and give up easy basket. John starkton couldn't score like nash, but he is better than Nash because he's a defense powers, he had less TOs and controlled tempo better.
I hadn't thought of it that way, but that could be playing into it. I can check to see if certain players' turnovers are more costly than others. My theory is that because the Rockets are playing more up-tempo this year and taking quicker shots without really setting up their offense, this puts them out of position defensively when they aren't able to capitalize. How often do we see a team go for a quick shot on a fast break and miss, and then the other teams run it right back on them? This must be happening to the Rockets more frequently this year than last year.
I find it astonishing that our half-court defense (after made FG/FT, missed FT) is actually better now.