Sports Reference Blog

Sometimes SR data finds its way into academic journals. Here's a summary Benjamin Campbell has written up on some of his findings about post-trade player performance:

"Although NBA GMs make mid-season trades for multiple reasons, one frequent objective is to improve

the short-term performance of the team. Since the rim is 10 feet from the floor everywhere from Hinkle

Fieldhouse to the Staples Center and the rules are the same everywhere, this seems to be a good

strategy. However, given the interdependent nature of basketball, trades present a challenge to short-

term performance because they disrupt the ability of players to productively play together. It is through

experience and time together that players can learn how to best play together, thus there is a learning

curve whenever a trade occurs. This learning curve impacts both the players joining a new team and the

incumbent players on that team that now have to learn to play with new players.

 

The learning curve for players to adjust to a trade is impacted by the size of a trade. For example, when

Raef LaFrentz, Nick van Exel, Avery Johnson, and Tariq Abdul-Wahad moved together from Denver to

Dallas in exchange for three players on February 21, 2002, they had less of a learning curve than a single

mover because they already knew how best to play with each other. However, their new teammates in

Dallas had a steeper learning curve because the incumbent players have to learn the idiosyncrasies of

four new, already coordinated teammates.

 

Using data from basketball-reference.com, a recent academic paper explores the learning curve

associated with single and multi-player trades on player performance over time. The authors find that

players who move from one team to another by themselves lose 2.3 percentage points from their true

shooting percentage on average, and take about 20 games to get back to their previous performance.

The true shooting percentage of players who move as part of a multi-player trade is not significantly

impacted. However, the reverse is true for incumbent players: players who are joined by one new

teammate experience no reduction in team shooting percentage, but players who are joined by multiple

teammates at the same time do experience a small (but statistically insignificant) reduction in true

shooting percentage. These effects are similar for both starters and little-used players alike.

The authors also show that moving with other players has a substantially larger positive effect on

movers’ individual performance when moving to teams with a losing record than when moving to teams

with a winning record. This suggests that it is easier for players moving together to import their existing

relationships in to low-performing teams than in to high-performing teams.

 

Together, the results highlight the double-edged sword of trading to improve the short-term

performance of a team. Trades may improve short-term performance by bringing in better players

and/or players that will eventually fit the team better. However, bringing in new players is disruptive to

all players on the team which erodes the short-term benefits of the trade.

 

For more information, see “Resetting the Shot Clock: The effect of comobility on human capital,” by

Benjamin Campbell, Brian Saxton, and Preeta Banerjee, which appeared in the February 2014 issue of

the Journal of Management."

This entry was posted on Monday, April 27th, 2015 at 1:05 pm and is filed under Academics, Announcement, Basketball-Reference.com. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.