Do the Warriors really play the right way?

What’s the Question?

Which NBA players make their teammates better?

Anyone that follows professional basketball knows that the NBA has realized a talent boom in the last 5-10 years. Popularity, attention, and league-wide revenue has been growing, as well as punditry and data. Fans of the league are riveted by such important, profound questions such as “is Kevin Durant a cupcake?

More importantly, the NBA is on the cutting-edge of data collection in sports. Thanks to the NBA’s partnership with STATS SportVU, they are tracking data well beyond the box score most of us have seen in a newspaper. SportVU is a system of 6 cameras hung from the ceiling that track ball and player movement 25 times per second to produce metrics such as secondary assists, miles traveled, made field goals defended at rim, and one frequency on pick and rolls, etc.

The Golden State Warriors have received high praise this season as the best team ever. They are frequently said to play the right type of basketball, that they’re unselfish, and that they make their teammates better.

Basketball is one of the most popular sports in America and by far my personal favorite. The strategy on and off the court is fascinating. It’s easy to give a big contract to the player who scored the most points or the MVP. But Russell Westbrook didn’t make it out of the first round of the playoffs. It’s a complex game and we finally have the means to answer the really complex questions that keep fans coming back.

What data do we need?

Lucky for us, the NBA has made the data they collect readily available on their website. Unfortunately, they do not make it readily available for download. This might require some text scraping, but some other fans have already done some work on this.

Variables of interest include:

• Real Plus/Minus
• Points Scored
• Points Scored Against
• Player Efficiency Rating (PER)
• Usage Rates
• Effective Field Goal %
• True Shooting %

Other variables will be considered as the model is constructed. I will use data from the 2016-2017 NBA regular season and postseason.

What methodology can we use?

I’ll use comparative statistics to analyze team differences with and without certain players. I will likely use linear regression to weigh the different dynamics of a basketball game and which aspects of a player truly make his teammates better.

Given the nature of plus-minus statistics, being calculated at a team level, lineup level, and player level, I may find value in a hierarchical model.

Ultimately, there are a few assumptions I’ll have to more fully address:

• How am I defining making your teammates ‘better’?
  • I’ll look at Real Plus/Minus while a particular player is on the court. This captures both an offensive and defensive perspective.
• How will I measure a player’s impact on this definition of ‘better’?
  • I will try to extract a player’s direct impact on his team’s Real Plus/Minus (i.e. points he scores or allows himself)
• And how do I determine the difference between making teammates better and a synergistic effect of particular teammates.
  • Comparing similar lineups with and without a particular player may shed light on this, but ultimately this question may not matter. The information is still useful in picking lineups that maximize a group of players’ value.

Who cares?

Besides the aforementioned pundits and fans, basketball organizations should care, players should care, agents should care, everyone who gets paid from basketball related revenue should care. Team strategy off the court is proving critical . It’s hard to gain an edge in a league with a salary cap and paying the best players and getting the best coach doesn’t cut it anymore. Being able to answer questions like these allow teams to find value where others miss it and optimize the resources they have.

Further iterations on this question would allow teams to understand not only which players impact their teammates, but which types of teammates best suit star players. This could help organizations tailor their teams around a foundation (e.g. how the Cavs build around Lebron James after Kyrie Irving’s request for a trade, or how to build around the new pairing of Chris Paul and James Harden for the Rockets).