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The NBA's 4 factors and how they correlate with winning

By Andy Larsen, KSL.com  |  Posted Nov 3rd, 2017 @ 11:55am


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SALT LAKE CITY — The Jazz had just lost to the Phoenix Suns, and head coach Quin Snyder wasn't happy. The team had turned the ball over 24 times in a loss to a team that had just fired its coach. Adding insult to injury, they allowed the Suns to grab 16 offensive rebounds.

"The fact that we were in the game even — to gift a team 40 possessions, you'd have to have a monumental shooting night to overcome that," Snyder said then.

Since then, the Jazz have rebounded, both literally and figuratively, with a 3-0 record. They're doing a better job of holding onto the ball, and when an opponent misses shots, they've started to clear the glass well.

But the experience was enough to make me wonder: how hard is it to win games in the NBA when you turnover the ball that frequently? Is there a "magic" number of turnovers you just have to avoid, or a certain amount of second chances you just can't give to your opponent?

And while we're looking at that, let's round it out by looking at the other "four factors," the four NBA stats that determine 96 percent of winning. How badly can a team shoot the ball and still have a chance to escape with a win? And what about the free-throw line: how hard is it to win games if you don't give yourself free points?

To investigate, I downloaded the team stats for every NBA game since (and including) the 2010-11 season. With 8,369 games in all, it would have been difficult to do manually, but Jason Roman's NBASense project helped me find the data I needed using the NBA's own API.

Then, it was just a matter of calculating the four factors for each game: effective field goal percentage (a measure of how well a team shoots), turnover percentage (what percentage of a team's possessions do they cough up the ball?), offensive rebounding percentage (what percentage of a team's own misses do they end up getting back?) and FT/FGA (how many times does a team get to the line, and how frequently do they make those freebies?).

After that, it was a matter of sorting those games by each of the factors and seeing how frequently that team won or lost games with a factor above or below that benchmark.

So let's take a look at my original question: how likely are you to win if you give up wads of turnovers? Likewise, how likely are you to win if you take good care of the ball?

If your team's TOV% is higher than this TOV%If your team's TOV% is lower than this TOV%
TOV%WinsLossesWin %% of gamesTOV%WinsLossesWin%% of games
68250827950%99%61209057%1%
78095816350%97%727420757%3%
87832796150%94%853940957%6%
97382766549%90%998870458%10%
106753715449%83%101621121657%17%
115942648148%74%112431189156%26%
125020570247%64%123352266856%36%
134072475246%53%134298361854%47%
143127380445%41%145243456753%59%
152273293244%31%156098544153%69%
161554217242%22%166816619752%78%
171007149740%15%177362687352%85%
1862398039%10%187747738951%90%
1936260937%6%198008776051%94%
2019336635%3%208177800551%97%
2110822433%2%218262814650%98%
2552119%0%258365834850%100%

It's less impactful than I thought! Even the Jazz, the highest-turnover team in the league, have only turned the ball over on 20 percent of possessions in one game this season, the aforementioned Phoenix contest. The data shows they still could have had a chance to win that if they did other things right. And keeping turnovers super low doesn't help too much either: keeping the ball to the highest degree only gives about a 57 percent chance of winning.

Let's look at rebounds: How many offensive boards do you need to win?

If your team's OREB% is higher than this OREB%If your team's OREB% is lower than this OREB%
OREB%WinsLossesWin %% of gamesOREB%WinsLossesWin%% of games
88298829350%99%8727649%1%
128085803350%96%1228534345%4%
147819769650%93%1455368345%7%
167483729951%88%16894108645%12%
186982669251%82%181396169545%18%
206485605952%75%202074249145%27%
225608517552%64%222776323246%36%
244845425553%54%243543415046%46%
264064341454%45%264320500246%56%
283207260955%35%285178579547%66%
302508191957%26%305940652448%74%
321829130458%19%326556709548%82%
34138687061%13%347000751448%87%
3689150964%8%367494787049%92%
3855130664%5%387828807049%95%
4035418266%3%408042820949%97%
44965165%1%448274831950%99%
48291566%0%488343835450%100%

Again, the correlation isn't very high! The teams with the lowest offensive rebounding rates still have won 45 percent of their games. Perhaps some of this is because the league's best teams over the past few seasons have eschewed the offensive glass in favor of transition defense. Getting a ton of offensive rebounds certainly helps, but it's not enough to guarantee victory either.

How about getting to the free throw line? Is there a magic number of shots that are useful there?

If your team's FT/FGA is higher than this FT/FGAIf your team's FT/FGA is lower than this FT/FGA
FT/FGAWinsLossesWin %% of gamesFT/FGAWinsLossesWin%% of games
68318827950%99%6519136%1%
88222810950%98%814926336%2%
108026777751%94%1035861237%6%
127689725251%89%12685112638%11%
147175652752%82%141195184939%18%
166516573753%73%161859264841%27%
185753480354%63%182617356842%37%
205025399756%54%203449448543%47%
224159311157%43%224211526244%57%
243412241359%35%244969597445%65%
262642171561%26%265741667046%74%
282033123762%20%286358714947%81%
30153285964%14%306877752248%86%
32111060765%10%327271776848%90%
3655026567%5%367823810849%95%
4026211969%2%408121825850%98%
441144870%1%448257832150%99%
48511775%0%488318835350%100%

There's more here. Getting to the line and getting those easy points might be a big factor in whether or not a team wins games. Of course, that also might be because the players who get to the line most are usually the league's best players, and it's good to have them on your team.

And finally, the big one: Is there a baseline amount of shots that you just have to make in order to get a win?

If your team's eFG% is higher than this eFG%If your team's eFG% is lower than this eFG%
eFG%WinsLossesWin %% of gameseFG%WinsLossesWin%% of games
328368834750%100%321234%0%
368362820250%99%3671694%1%
408277754352%95%4010286411%6%
428139686654%90%42230150713%10%
447885591957%82%44486246516%18%
467453482461%73%46923356121%27%
486741364065%62%481636474926%38%
505916267769%51%502738600731%52%
524681156775%37%523700681035%63%
54359391380%27%544787746439%73%
56257148684%18%565809789042%82%
58171321889%12%586670815445%89%
6010948593%7%607305828947%93%
643221396%2%648048835649%98%
6867199%0%688304836850%100%

Ah, yes, shooting shots is an important basketball skill. If you can keep your opponents under 40 percent eFG%, or if you can score over 60 percent, you're nearly guaranteed to win the game. While this is obvious, you kind of begin to understand why the NBA's coaches have started to ignore offensive rebounding in favor of getting back in transition defense: the shot seems to just be a bigger factor in winning.

And of course, this seems to also back up another NBA coaching tenet: "It's a make or miss league." Whatever you can do to get yourself good looks and make them seems to be worth doing.

Andy Larsen, KSL.com
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