Newspaper article The Canadian Press

New Study Suggests NBA Scorekeeper Bias Impacts Box Scores across the League

Newspaper article The Canadian Press

New Study Suggests NBA Scorekeeper Bias Impacts Box Scores across the League

Article excerpt

Study: Bias exists among NBA scorekeepers


VANCOUVER - Growing up playing youth basketball in Nova Scotia, Matthew van Bommel didn't think much about the scorekeepers sitting courtside.

As long as the point totals were correct, there was no need.

But while working on his masters in statistics years later, van Bommel noticed something.

The NBA had revoked some players' triple doubles -- an in-game achievement where an individual reaches double digits in three separate categories -- after it was determined some of their more dubious assists couldn't be justified.

That, along with a story about a rogue NBA scorekeeper who purposely fudged numbers without getting caught while working for the Vancouver Grizzlies in the 1990s, got van Bommel thinking.

Is there a bias among scorekeepers?

A new Simon Fraser University study van Bommel co-authored with Luke Bornn that looked at the 2015-16 NBA season suggests there is bias when it comes to how assists and blocks -- two of the most subjective categories due to vague definitions -- are counted by the league's 30 team-hired scorekeepers.

The NBA states assists, the stat researchers focused on most, are given "only if, in the judgement of the statistician, the last player's pass contributed directly to a made basket."

That sentence alone leaves a lot of room for interpretation, van Bommel and Bornn thought.

The pair analysed billions of lines of data from NBA cameras that track the movement of both players and the ball on the court 25 times per second in every game. Their mathematical model monitored on-court actions, taking into account styles of play, while omitting overtime periods and neutral site games.

They matched results to the box scores, concluding that scorekeepers have a wide range of opinions on what constitutes an assist.

"We quantified two different scorekeeper effects," said the 23-year-old van Bommel. "There's how generous a scorekeeper is, which is how often they give assists to any player.

"The other side is the actual bias where there's some scorekeepers that give more assists to the home team, and some scorekeepers that give more assists to the away team."

The Utah Jazz scorekeeper was found to be especially frugal with assists, awarding 9.7 fewer on average per game compared to the one employed by the Atlanta Hawks.

"We're not trying to say this is anything intentional or anything malicious," said van Bommel. "The NBA just has these ambiguous definitions, especially for assists. This leads to inconsistencies in scorekeeper opinion."

So why worry about a couple of assists that don't impact the final score? In the world of big-money daily fantasy sports leagues where participants select a roster to compete for cash prizes, the implications could be far-reaching. …

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