The Magic Number is 45

Is there a magic number when it comes to defense? According to some coaches, there is.

Mike Wells of the Indianapolis Star talked to Pacers head coach Jim O’Brien about his team’s goals defensively…

O’Brien said his team has to hold opponents to less than 45 percent from the field while also getting better play from team leader Granger. Opponents shot better than 45 percent against the Pacers 39 times and scored at least 110 points against them 27 times last season.

“We want to be in the top 10 in the league in field goal defense,” O’Brien said. “If you can be a team that holds opponents under 45 percent for the year, you’d be a playoff team. That’s our defensive goal.”

Sixers coach Doug Collins has the same target.

“If we keep our opponent under 45 percent shooting, we think we have a chance to win some games,” Collins told me on Saturday.

Avery Johnson doesn’t just talk about it. He’s got a sign up in the Nets’ practice gym that reads “Defensive FG% = 44%.”

Now, this is obviously a simplistic way of looking at things. For one, saying that holding opponents under 45 percent doesn’t account for how well your team does offensively. And second, there are other factors that affect how good your defense is: your opponents’ 3-point shooting, forcing turnovers, fouling, and rebounding.

If you keep your opponent under 45 percent shooting, but allow them to get to the line 40 times in a game, they’re probably still going to score a lot of points. You’ve also got to control the boards, obviously.

It’s possible that neither O’Brien nor Collins are versed in advanced statistics and would rather talk points per game and field goal percentage than points per possession. It’s also possible that they have autographed copies of Basketball on Paper, but prefer to keep things simple for their players and the media.

Either way, for the purposes of this blog post, I went over the 10 years of data, and found the following…

In the last 10 years, 135 teams have held their opponents under 45 percent shooting (actually 44.950 percent) over the course of a season, and 102 of those teams have made the playoffs. So if you hold your opponents under 45 percent, you’ve got a 76 percent chance of making the playoffs. That’s pretty good, but not quite a magic number.

But perhaps we’re looking too far back. After all, league-wide offensive efficiency has come a long way in the last 10 years.

And indeed, over the last four seasons (2006-07 through 2009-10), 29 teams have held their opponents under 45 percent shooting, and all 29 have made the playoffs. The last teams to finish under the magic number and fall short of the postseason were the Rockets, Timberwolves and Jazz in 2005-06.

So yeah, I’d say that 45 percent is a good target. The numbers back it up.

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John Schuhmann is a staff writer for NBA.com. Send him an e-mail or follow him on twitter.

One Comment

  1. think says:

    wow… thats how the number’s game has become LOL.

    anyway, as I was playing before, we only have one mantra in mind… ” we have to score, and we dont let them score” haha.

    Thats just the principle behind almost any sport. But right now, the stats and numbers game really influences how the game is being played. Too much fantasy games, too much team effeciency analysis. Its just human nature to understand things thats why we try to quantify them. But at the end of the day, its just the passion of playing the game that you love and the will to win… well, thats just my opinion.

    Its just weird for me to hear from my coach telling me, instead of “we play and win, one game at at time”, he’ll say “we’ll limit them under 45% FG, one game at a time”

    just weird.