NBA perimeter defense experiments with Bucks F Luc Mbah a Moute

I really like Luc Mbah a Moute. Maybe I should love his game, or maybe it's not worth getting too excited about, but I like him anyways and it has everything to do with defense. What bothers me is that I've never taken the time to dig into his stats to truly appreciate his impact on the Milwaukee Bucks' defense. Then again, perimeter defenders are frustrating to me as a matter of course.

To make judgments on the quality of individual perimeter defenders in the NBA is to make at least a minor leap of faith. Team defense is almost too delicate an organism to pick apart the contributions of defenders operating beyond 15 feet from the rim. The data is messy, individual matchups are routinely asymmetrical, isolation plays test different skills than pick-and-roll sets, and reputations threaten to muddy the process at nearly every turn.

So should we throw up our hands and declare the search useless? In the spirit of quality defense, I plan on giving my full effort. Here's a bit of background on why I want to take a closer look.

I've long believed that interior defenders like Andrew Bogut are inherently more valuable than perimeter defenders like Luc Mbah a Moute. To me, the potential impact of a defender is directly related to the distance that defender is normally spaced away from the rim. My stubbornness is based on the geometry of NBA defense. League shooting percentages are highest in the paint thanks to the shorter distance to the rim, and interior defenders are best-equipped to affect those short angles and consequently pull down the efficiency of opponents by disrupting the "easiest" shots on the floor.

Goalies in soccer charge at strikers on breakaways to cut down angles for shots, and interior defenders in basketball can impact penetrating ball handlers and high-efficiency hopefuls in the same way - easy shots can turn into very difficult ones for the offense if a great defender is anchored near the goal to alter angles on shots. As an added bonus, paint protectors can defend multiple players in a single sequence because the area of coverage is smaller than it is for someone working on the perimeter and trying to rotate across the court. Just visualize the area of the half circle restricted area and compare it to the area of the half circle we know as the three-point line. Simply put, interior defenders can cover more important regions on the floor than perimeter defenders.

When I say interior defenders are inherently more important than their teammates working on the perimeter, it doesn't mean the perimeter defenders can't be important too. That's why I carefully used the word "more" as my qualifier. Mid-range shooting percentages typically hover around 39% for a league average, while conversion rates in the paint jump well beyond 50%. Mid-range shooters often beat themselves, as far as I'm concerned.

So the real question is whether perimeter defenders can suppress scoring efficiency in the paint and behind the three-point line. The persuasive power of prevailing reputation took a major hit for me when I looked up Arron Afflalo's defensive performance from the 2011-12 NBA season.

First, some context: during the '09-10 and '10-11 seasons, Afflalo earned a combined total of seven points in the "others receiving votes" category for All-Defensive honors. During that same span, LRMAM collected 10 total points, Andrew Bogut tallied nine and Andre Iguodala managed 17. Afflalo entered the '11-12 season with an established reputation as a top perimeter defender, a trait that helped him land a juicy five-year, $43 million deal with the Denver Nuggets.

Without looking at the stats, I'd venture to say most people still think Afflalo is a top defender -- he's earned the trust of NBA fans; he's in the club now. In a mind-blowing twist, the former UCLA star allowed opponents to produce a whopping 0.98 points per possession over 779 plays last season, which qualified him as the No. 422 defender in the league and among the worst wings in the NBA, according to MySynergySports.com. How did something so awful happen to a proven perimeter defender so often? Maybe it's also worth asking why have the Nuggets been a better defense with Afflalo on the bench?

The point here is not to pick on Afflalo, it's to try and dig at some of the questions and assumptions that make evaluating perimeter defenders so difficult. The obvious response to the Afflalo questions is to say elite perimeter defenders are asked to go man-to-man against the best scorers in the NBA every night, so individual numbers won't ever look great. That makes a bit of sense, but there still has to be some measuring bar.

I've assembled a list of big-time NBA wing scorers -- LeBron James, Kevin Durant, Carmelo Anthony, Danny Granger, Joe Johnson, Kobe Bryant and Paul Pierce -- to stack up against guys known across the league as top-notch perimeter defenders. The reputation of a perimeter stud like Luc Mbah a Moute will be put to the test by measuring on-court defensive impact relative to the normal shooting averages and advanced stat ratings from the scorer group. Sample sizes are small for these individual matchups, so I combined the stats to create three-year averages.

It may not be fair to hold perimeter defenders responsible for an entire team defense, so I avoid that problem in this test. It's a simple man-to-man comparison. Do these "stoppers" really do much to stop top scorers? The big assumption in my test is that the top defenders matchup against the top scorers when both are on the floor, but that's what top defenders are supposed to do.

This introductory piece will serve as the foundation for a StoryStream where I will present the data on how well LRMAM managed to fare against LeBron James, Kevin Durant, Carmelo Anthony, Danny Granger, Joe Johnson, Kobe Bryant and Paul Pierce. Stay tuned as the numbers for the last three years are revealed for each matchup between the Bucks' ace defender and some of the top scorers in the league.