APBRmetrics

**Jon** **Nichols** · Joined: 18 Aug 2005 Posts: 370

As I'm going through the play-by-play data at Basketball Value, I notice that some of the entries list the result of a play as a "dunk shot" while others call them "slam dunk." What makes a dunk a slam dunk? Is there actually a difference or is this just an effect of different scorekeepers?

Thanks,
Jon

Ryan J. Parker · Joined: 23 Mar 2007 Posts: 711 Location: Raleigh, NC

Would it make a difference either way?
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**Jon** **Nichols** · Joined: 18 Aug 2005 Posts: 370

Probably not. I was just curious as to why this happens.

Ryan J. Parker · Joined: 23 Mar 2007 Posts: 711 Location: Raleigh, NC

Come back and post more "why does this happen in the play-by-play" after you've done some more work with it. I'm pretty sure you'll have more Shocked

moments than this! Cool

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IrishHand · Joined: 15 Jul 2009 Posts: 115

The software that the NBA stat crews use have both "dunk" and "slam dunk" as options for shot type. I assume that the latter was meant to highlight a particularly spectacular dunk, but there was never any guidance on the topic iirc. They're the same for any analytical purpose I can think of.

Mike G · Posted: Fri Jul 24, 2009 11:43 am Post subject:

A regular 'dunk shot' is one that gets the job done. Often the player could lay it in, with or without using the glass; but he can dunk it, so he does.

A 'slam dunk' is one in which a defender would have to retract his hand or get it torn off at the rim. The power in the dunk is part of the effectiveness of the shot.

Of course, there are players who like to dunk with unnecessary force, every time. And occasionally someone will block a slam dunk attempt. But those are the distinctions I'd make.
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**Jon** **Nichols** · Joined: 18 Aug 2005 Posts: 370

Interesting. Well if there really is a difference, I think it's useful to separate them the way they do. Thanks.

kjb · Joined: 03 Jan 2005 Posts: 865 Location: Washington, DC

Maybe "slam dunk" is used only in games broadcasted by Jack Ramsay.

Sandy Weil · Joined: 19 Jun 2008 Posts: 20 Location: Boulder, CO

Be careful when working with the additional details of the shot type beyond the primary descriptors (jumper, dunk, layup, hook, tip). The presence of secondary descriptors (running jumper, running hook, reverse dunk, reverse layup, etc.) are strongly biased. A quick look at FG% by shot type will show you that players are much more likely to make a (your descriptor here) layup than a plain layup.

This is not because a running, turnaround, or banked hook is easier than a vanilla hook. It is because the scorekeeper is more likely to supply the extra details after a make.

The court-side play-by-play entry person has more time to record additional details after a made shot than they are after a missed shot (after which, as play continues, they need to record a rebound, possibly more shots by other players, etc.).

For my work, I've stuck to using only the primary shot type descriptors (listed above). You can obviously draw your own conclusions and work with the data in your own way, but you should be careful with these.

**Jon** **Nichols** · Joined: 18 Aug 2005 Posts: 370

Thanks, Sandy. That's good advice and something I started to notice as I looked through the data. I don't think it was a coincidence that certain teams featured a lot of players with "running layups" while others did not.