How the Shooting Abilities of Shooting Guards, Power Forwards, and Centers Affect Offenses
Jul 26th, 2009 by Jon Nichols

Not too long ago I ran a couple of studies measuring the effectiveness of three-point shooting ability for point guards and small forwards. The general idea wouldn’t be complete without a look at the remaining three positions.

Using the lineup data at BasketballValue, I’ve split the lineups into three groups: those featuring a player from each position who shoots 40% or better on threes, those featuring one who shoots 30% or less, and the remainder. For each group, I’ve calculated the average Offensive Rating. In addition, the lineups are split between those at home and those on the road. The results for shooting guards are in the graph below:

And here are the frequencies for that position:

The results for shooting guards are very similar to those of point guards. Not surprisingly, having a player at those positions with the ability to shoot accurately from long distance greatly improves the success of your offense. One thing that is different is the frequencies. As you can see above, not too many shooting guards shoot less than 30% on three-pointers. However, the frequencies for shooters above 40% aren’t too high, either.

Up next are the power forwards. For this position, I had to alter the criteria a little bit. To ensure adequate sample sizes, I had to change the definition of great shooters to those above 38% on threes, and poor shooters to those below 28%. It’s a minor change, but it’s fair because of the relative lack of big men who can shoot well from the outside.

At home, it doesn’t seem to matter if your power forward can shoot. The four categories are essentially identical. On the road, it appears that your team gets a significant boost if your power forward can shoot threes at a higher rate than 28%. He doesn’t have to be spectacular in this area; he just needs to be adequate.

Finally, let’s take a look at the centers. I had to make yet another change for this position. Even fewer centers can shoot three-pointers accurately, so I removed the cutoff points altogether. Instead, I classified centers as shooters or non-shooters. The difference was whether or not the player had a large amount of three-point attempts. Of course, by changing the criteria from accuracy to attempts, I changed the dynamic. However, given the scarcity of great-shooting centers, it was necessary.

The center results may not be directly comparable to those of power forwards because of the different criteria, but they appear to be the inverse. On the road, it doesn’t matter if your center likes to shoot from the outside. At home, however, it is beneficial. Either way, the differences aren’t significant enough and the sample sizes too small for me to make a definitive statement.

So there you have it. To recap:

-For point guards and shooting guards, it is beneficial for your offense to have players at those positions that can shoot threes effectively (however, there are some complications. Go to http://basketball-statistics.com/articles.html for more studies I did on point guards).

-For small forwards, it is best to have a player closer to average (between 30% and 40%). This may be the result of sharpshooting small forwards being specialists that are weak in other areas.

-For power forwards, it all depends on the location. At home, it doesn’t matter how well he shoots threes. On the road, it’s great if he can shoot them at 28% or higher.

-For centers, the answer remains unclear. There simply aren’t enough great shooting centers to reach a reasonable conclusion.

At Which Positions Are Bad Players the Most Detrimental?
Jul 23rd, 2009 by Jon Nichols

In my last study, I looked at the importance of great players to a team’s success. Today, I will be doing the opposite, instead focusing on the weaker players. The methodology is the same, only I will be using players with an Adjusted Plus-Minus below -3 rather than above three. For further details on my methodology, click on the article above. Without further ado, here are the results:

And the home/away splits…

It appears the two positions you don’t want to be weak at are center and small forward. On the other end of the spectrum, it appears you can manage a lot better with a bad point guard. Of course, it’s best to have as many good players as possible, so ideally you don’t have to “deal with” anything.

At home, weak players at the guard position don’t appear to be particularly disastrous. In fact, lineups featuring a point guard with an Adjusted Plus-Minus below -3 still on average tend to be better than their opponent. On the road, it hurts much more to have a weak guard, especially a 2-guard. Regardless of location, center and small forward are two positions where you can’t have a struggling player.

Just like I did with my last study, I’m going to look at two potential hidden issues. The first is sample size.

There appears to be an adequate amount of bad players at each position to make this study valid. Interestingly, there are more bad players at point guard than at any other position. Originally I would have guessed centers would be the weakest.

The next step is to calculate the average Adjusted Plus-Minus for each position among those that qualify. For example, if there are 20 point guards with an Adjusted Plus-Minus of -3.01, that position will look not as important because the players in the study really aren’t that horrible in the first place. What do the numbers say?

With the exception of small forwards and possibly power forwards, the numbers appear to be pretty even across the board. This further supports the evidence that having a weakness at small forward is a major problem. Even though the small forwards in this study weren’t as bad as the other positions, they still had a more negative effect than any other position besides center.

Finally, I’d like to relate this back to my original study. As you may recall, I suggested that small forwards and centers (especially on the road) are often the most important players to a team’s success. Today’s results support that assertion. Not only does having good players at these positions greatly improve your team, but having weak players at these positions worsens your team. On the other hand, point guards appear to be much less important. Both good and bad ones have less of an impact.

Like I said in the original article, these studies are by no means the final authority. I only looked at two potential complications, and in reality there could be many more. Further studies should isolate the positions further and perhaps explain in more detail why exactly certain positions appear to be more important than others. I would also like to look at the results of previous years, which is something I may get into soon.

At Which Positions Are Great Players the Most Important?
Jul 19th, 2009 by Jon Nichols

Using the lineup data at http://www.basketballvalue.com, as well as the Adjusted Plus-Minus ratings, I’ve tried to figure out which positions are most crucial to a lineup’s (and team’s) success. My method was pretty simple. I calculated the average net rating (offensive rating minus defensive rating) of all lineups featuring a player with an Adjusted Plus-Minus of greater than three at each position. For example, if the average net rating for small forwards is five, then that means that all lineups featuring a good small forward (Adjusted Plus-Minus greater than three) beat the opposing lineup by an average of five points per 100 possessions. The easiest way to understand this is to look at it graphically:

Let’s look at the home and away splits:

Overall, it appears that small forwards are the most important, followed by power forwards, centers, shooting guards, and point guards. I’ve heard people suggest small forwards are crucial to a team’s success in the past. Three of the remaining four teams in the playoffs last year featured a small forward as their main playmaker. And as my study on the shooting abilities of small forwards showed, it’s best not to have a specialist at that position. What you need is a player who can do it all because that position appears to be very important to your team being successful.

Things get especially interesting when you look at the home/road splits. At home, small forwards still reign supreme. However, the little guys essentially catch up to the big men in terms of importance.

On the road, though, it appears having a solid interior is crucial. The importance of great guards is minimized greatly and centers and power forwards are well ahead of the rest of the pack.

Of course, there are a few potential concerns with this data, and I will explore two of them in this article. First, as always, there’s the question of sample size. Maybe point guards are just getting a bad rap because the sample size is too small and the ones that do qualify haven’t had that much success. Let’s take a look at the frequencies of each position having a player with an Adjusted Plus-Minus greater than three among all lineups:

I would say the sample sizes are pretty big. An observation I had was the relative lack of quality centers compared to other positions. Perhaps the complaints about there being no good centers nowadays are valid.

A second concern might be the quality of players in each position among those that qualify. In other words, if there are 20 point guards with an Adjusted Plus-Minus above three but they’re all at 3.01, it’s no surprise that they’ll look worse than the other positions. To see if this is a problem, I calculated the average Adjusted Plus-Minus for each position among those that qualify:

Three of the positions (point guards, power forwards, and centers) are bunched together, one is clearly lower than the rest (small forwards), and one is clearly higher (shooting guards). This evidence further supports the original conclusion I made that small forwards are the most important. After all, we have the weakest group to choose from at that position yet they still have the most positive effect. On the other hand, there are a lot of excellent shooting guards in the NBA, yet their impact is much less significant. And still, I have yet to find an excuse for point guards. They are often seen as the floor general and the player crucial to a team’s success, but remember who the two starting point guards in the Finals were (Derek Fisher and Rafer Alston). Of course, there are still potentially hundreds of hidden variables that could have an explanation for why my data underrates them.

In a few days, I will follow up on this study by taking a look at the other side: bad players. At which positions are bad players the most detrimental to a team’s success? Not only will it be a unique compliment to this study, but it also may shed some light on why today’s results look like they do. Stay tuned.

Trying to Understand the Point Guard Results, Part III: Combining Three-Point Percentage and Three-Point Attempts
Jul 16th, 2009 by Jon Nichols

So far, I’ve run two studies trying to make some sense of my original study on the importance of three-pointers for point guards. First, I factored in true shot percentage. Next, I re-did the original study using career three-point percentage instead of the current season’s percentage.

Today, I’m going to look at the interplay between three-point percentage and three-point attempts. So far, I’ve established that at least in some ways, three-point shooting is important for point guards. However, it makes sense that a player that can shoot threes not only efficiently but also often will be even more effective. It may even be possible that being an average three-point shooter but attempting a lot of them is more useful than being an accurate but timid shooter. After all, if a player keeps hitting threes, the defense will inevitably be forced to adjust and leave other players more open.

To see if there is some truth to this, I first divided the point guards into three categories based on percentage: those with a 3PT% above 40%, those between 30% and 40%, and those below 30%. I then split those three categories into nine based on the amount of attempts a player had. For each category, I calculated the average Offensive Rating of all the lineup combinations that featured one of those players. The results are below:

To see the amount of lineups that qualified for each category, see below:

As you can see, not enough players qualified for the top right and lower left categories, and that’s a good thing. That means that the best shooters aren’t afraid to fire away and the worst shooters know their limits (to an extent). Another observation is that accuracy is more important than frequency. The players with the highest percentages had the most positive impacts on their offenses, regardless of the number of attempts. Additionally, it is better to be more efficient with a medium amount of attempts than less efficient with a higher amount of attempts.

Beyond that, there are many more observations to be made. There are also many other ways I could qualify the importance of three-point shooting for point guards. In the future I will do some more research as well as gauge the importance of three-point shooting for other positions.

Trying to Understand the Point Guard Results, Part II: Using Career Three-Point Percentage
Jul 14th, 2009 by Jon Nichols

A second concern about my point guard study, besides the complications of true shot percentage, is the possibility that the relationship between three-point shooting in point guards and increased team Offensive Ratings is a matter of correlation and not causation. Perhaps, the theory goes, a point guard shoots a high percentage from long distance because the team is good at offense, rather than his three-point shooting being a reason why the offense is successful.

There are number of ways to get some clues to see if this is a problem. A simple method that I have chosen is using the point guards’ career three-point percentages rather than the current season’s percentages. The career percentage should be a more accurate indicator of whether or not the player is truly a good shooter from long range and not just a product of offense. Of course, if a player has spent his entire career with one team the results may be less useful, but nevertheless we push forward:

As you can see, instead of using the cutoff points of 30% and 40%, I changed them to 32% and 38%. I did this because there are fewer players that have career percentages as extreme. 22.73% of home lineups featured a point guard with a career three-point percentage greater than 38%, and 33.95% featured a player with a percentage lower than 32%. On the road, those numbers were 23.06% and 34.07%, respectively.

The results are practically identical to those of the original study. I think we can safely say that using career three-point percentage instead of current percentage does not really make a difference.

Trying to Understand the Point Guard Results, Part I: Factoring in True Shot Percentage
Jul 12th, 2009 by Jon Nichols

In the point guard study I performed last week, a few questions arose. Perhaps the most important and potentially the most problematic was the question of whether or not three point percentage is useful simply because it raises a player’s overall true shot percentage (and therefore efficiency). If the players with the highest three point percentages also had the highest true shot percentages, it’s not much of a surprise that three point percentage leads to a positive impact on the team’s Offensive Rating.

To try to answer this question, I factored in true shot percentage to the original data. I broke the point guards down into four groups: those with above average 3PT% and above average TS%, those with above average 3PT% and below average TS%, those with below average 3PT% and above average TS%, and those that were below average in both. Theoretically, if three-point percentage is valuable independently of true shot percentage, then point guards with a high 3PT% should have very positive results on their team’s Offensive Ratings regardless of their true shot percentages. Of course, some complications do arise when doing the analysis this way, and I will get into that later. For now, here are the results:

Before I get into analyzing those tables, I should get into the complications. The biggest problem is still the fact that a high 3PT% correlates with a high TS%. Let’s look at an example. If Player A is in the high 3PT%, high TS% group, it is likely he’ll have a higher TS% than Player B, who is in the low 3PT%, high TS% group. Even though they are both in high TS% groups, Player A is a great three-point shooter, and that happens to be a very efficient shot. To see what kinds of problems those complications cause, let’s take a look at the averages:

The latter of those two tables is what we care about the most. As we can see, the problem is much more of a concern among the below average TS% groups. In those two, having a point guard with a high three-point percentage makes all the difference. In the two above average TS% groups, the difference is only about two percent, which is significant but not very substantial. Let’s keep this in mind as we go back to analyzing the original three tables…

When we look at the table for “ALL,” the original study seems to be invalidated. The Offensive Ratings follow the true shot percentages – the highest average true shot percentage is in the above average 3PT%, above average TS% category, and that’s where the highest Offensive Rating is. The two second-place categories match up, and so on. Basically, all that really matters is the true shot percentage of your point guard, not his three-point percentage. What happens when we look at the home/away splits?

This is where things get interesting. First, let’s look at the “Away” results. Here, it is pretty clear that true shot percentage is all that matters. The two high TS% categories fare much better than the two low ones. In fact, even though the high 3PT%, low TS% category has an average TS% nearly five points higher than the low 3PT%, low TS% category, the difference in Offensive Ratings is insignificant. It’s almost as if the ability of your point guard to shoot three pointers is a detriment on the road!

At home, things swing completely. As far as I’ve noticed, there are two results that indicate that three-point shooting for point guards at home is especially important. First, there is the difference in the two above average TS% categories. Despite having an average difference in TS% of just about two percent, the difference in Offensive Ratings is nearly five points per 100 possessions. Secondly, look at the difference between the above average 3PT%, below average TS% group and the below average 3PT%, above average TS% group. Despite the former having a true shot percentage over six points lower than the latter, the Offensive Ratings are close. The two observations I made in this paragraph don’t really make any sense, unless of course there’s something special about three-point shooting for point guards when you’re at home.

I’ll leave it to you to figure out reasons why this may be so. I’ve got a couple of ideas, but they are all just guesses. There are also a lot of other observations that can be made about all of the data, and certainly a lot of spin-off studies could be performed.

So to recap, three-point shooting for point guards appears to be much more important at home than on the road, regardless of true shot percentage. In addition, I still don’t want to undersell the importance of three-point shooting. If shooting the long ball effectively is the best way to become a more efficient player, then there really is something to three-point shooting. It just may be the case that it doesn’t necessarily improve the performances of your teammates, at least not on the road.

How the Shooting Abilities of Small Forwards Affect Offenses
Jul 10th, 2009 by Jon Nichols

The small forward position is one of the most critical positions in basketball. In most cases, the other four positions have specific responsibilities that don’t change a whole lot from team to team. However, the roles of small forwards are varied. Some teams use them as scorers, others as ball-handlers, others as defenders, etc. The goal of this study today is to determine the importance of three-point shooting ability in small forwards.

Using the lineup data at http://www.basketballvalue.com, I’ve split the lineups into three groups: those featuring a small forward who shoots 40% or better on threes, those featuring one who shoots 30% or less, and the remainder. For each group, I’ve calculated the average Offensive Rating. In addition, the lineups are split between those at home and those on the road. The results are in the graph below:

27.01% of home lineups feature a small forward shooting better than 40% on threes, and 21.22% feature one shooting less than 30%. On the road, those numbers are 26.56% and 21.62%, respectively.

The results are a bit surprising. Least surprising is the fact that if your small forward is a liability from long range, your offense tends to suffer. Clearly there is some benefit to being able to spread the floor. What is surprising is the fact that lineups featuring a sharpshooter at the small forward position also tend to be worse (although only slightly). Perhaps this reflects the fact that three-point specialists are often limited in other areas.

It appears the solution is to have a small forward who shoots somewhere between 30% and 40%. Again, this isn’t because missing shots is in some way beneficial. It’s most likely because the best shooters are the most likely to have the biggest weaknesses in other areas.

I don’t want to generalize too much, though, and there could be a number of hidden explanations for this. For now, I’ll present the data and let you draw your own conclusions.

How the Shooting Abilities of Point Guards Affect Offenses
Jul 8th, 2009 by Jon Nichols

Although they all generally have the same duty (run the offense!), different point guards in the NBA possess a variety of skills. Whether they are big or small, quick or fast, or aggressive or passive, they come in all shapes and sizes. As it turns out, some of the game’s best shooters run the point. Is the ability to shoot three-pointers well a key skill for point guards? Today I’ll take a look.

Using the lineup data at http://www.basketballvalue.com, I’ve split the lineups into three groups: those featuring a point guard who shoots 40% or better on threes, those featuring one who shoots 30% or less, and the remainder. For each group, I’ve calculated the average Offensive Rating. In addition, the lineups are split between those at home and those on the road. The results are in the graph below:

25.6% of home lineups feature a point guard shooting better than 40% on threes, and 30.05% feature one shooting less than 30%. On the road, those numbers are 25.62% and 30.32%, respectively.

It appears as though the ability of your team’s point guard to shoot the three well is very important. Overall, the difference is more than three points per 100 possessions. Similarly, if your point guard struggles with his outside shot, your offense will struggle.

Beyond that, I don’t want to say too much. It’s too easy to make bold statements without considering some of the underlying factors, so I’ll just present the data as is. Feel free to draw your own conclusions, though.

The Impact of Top Shot Blockers on Offensive Success
Jul 6th, 2009 by Jon Nichols

The league’s most skilled shot blockers are certainly fun to watch, but are they effective? Although preventing a shot attempt appears to always be a positive thing, there is something to be said for solid interior defense without making the spectacular play. To try to answer the original question, I’ve decided to run a quick study using the lineup data at www.basketballvalue.com.

The lineup data includes each different matchup of five players versus another five that took place during the 2008-09 season. First, I calculated the league average home and away Offensive Ratings. I then calculated the same averages for the lineups that were facing a top 20 shot blocker (based on blocks per 48 minutes). To see what effects those shot blockers had on their own teams’ Offensive Ratings, I calculated those averages as well.

As you can see, having a shot-blocking presence does not appear to improve your defense considerably. This difference is only noticeable when your team is on the road. However, these numbers are largely influenced by Shaquille O’Neal, a top shot blocker who played on a team that both scored and gave up a lot of points, bringing the numbers back to average.

The final verdict: shot blockers do not have a tremendous impact on lowering the opponents’ offensive efficiency. In a world without Shaq, though, things may be different…

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