APBRmetrics

I know this isn't strictly a stats-centric topic but I thought this would be a good place to get feedback from people who know what they're talking about…

I've been working with a couple of friends on building an NBA roster management model that allows the user to enter moves and see if they comply with the CBA and what impact they have on available resources. The tool is an Excel model so it exists in two formats. We host it as a web app at www.roster-builder.com (give it 5 seconds to load) and also make the underlying workbook, with a little bit of helpful VBA, available via dropbox.

There are sites out there (Sham Sport, Hoops World, etc) that are great at tracking what has happened but we're trying to give people a resource to test out their ideas for future moves.

How does it work?

When you open the tool you can choose any team from a drop-down and it will populate their current roster. From there, the tool will lead you through the basic process to build a team. Players are classified as having been on the roster at the start of the league season or acquired during the year as this impacts available moves and for that they are listed on separate sheets. From this baseline you can select what actions you want to take; from removing players, trading them, signing new players via cap space or using exceptions.

The tool is laid out in a series of "Steps" that you can move back-and-forth through. Each move will update other sections of the tool and re-calculate your salary cap space and available contract exceptions. Many moves create a cascade so, for example, if you say you want to waive a player via the stretch provision they will then appear in that section to enter their contract details. The steps are a suggestion for how to move through your roster but you don't necessarily have to follow everything in the order that's laid out. For specific instructions, click on the "Instructions" sheet within the tool.

Things the tool does well

• Gets the current roster and immediately available moves right
  Calculates the correct cap and tax totals at the end of all your decisions
  Calculates the maximum amount of salary cap space your decisions could create in the free agents section
  Calculates the contract exceptions you would have available and allows you to split them up
  Covers a wide range of moves, including the amnesty clause, stretch provision and buy-outs
  Tries to figure out the player you are trying to acquire to give you a shortcut to their previous salary and years of service
  Formats everything nicely at the end and tells you if you "passed" some basic CBA tests

Things the tool doesn't do as well

• The tool is meant to work for a single team so trades are a challenge. You should test your trades in the ESPN Trade Machine before entering them into the model.
  We can't make you enter reasonable decisions so if you think you enter a trade for Lebron it won't tell you that it's not going to happen.
  You can type in the names of players you want to sign however you want, but it will only pull up their previous salary information if you type it exactly as it exists on their current team's sheet.
  A lot of decisions have a cascading effect. That means the order of moves makes a big deal but we can't model all of that out. We built this to assume the moves happen in an order that creates cap space but that isn't always the plan. We've entered in the moves that have already happened this year so this isn't a huge deal right now; it matter more in the offseason.

We do this as a hobby so I really would appreciate any feedback. It's currently in the "in-season" form and we make it look a little different in the offseason because activities and priorities change. I also have to give credit to Larry Coon, basketball-reference.com, shamsports.com and hoopsworld.com because I get all this information from them, just like everyone else.

Thanks for sharing the tool. I've looked at it briefly and will return later. Depending on how much you want to promote it, you might post it at various realgm forum sections, some of the more serious team blogs and other analytic blogs.

side note:

The Celtics still have a cap hold for Dana Barros? He appeared in one game in April of 2004: http://www.basketball-reference.com/box ... 70IND.html

The Jazz have one for Ostertag.

The Spurs have holds for Van Exel and Stoudamire.

The Lakers have by far the most including Brian Shaw, Mitch Richmond and John Salley!

dbabbitt wrote:side note:

The Celtics still have a cap hold for Dana Barros? He appeared in one game in April of 2004: http://www.basketball-reference.com/box ... 70IND.html

The Jazz have one for Ostertag.

The Spurs have holds for Van Exel and Stoudamire.

The Lakers have by far the most including Brian Shaw, Mitch Richmond and John Salley!

This actually made me realize the cap holds were out of date. I lost a bunch of updates while I was working on the current version and this was apparently one thing I missed doing again. The Jazz actually renounced their holds this offseason so they don't have Ostertag in their accounting any more. Both versions have now been fixed. My favorite cap hold is that the Spurs still have one for Jacque Vaughn… who's obviously now a head coach.

A lot of people ask about cap holds but they hang around just because there's no reason to renounce them if you're over the cap. There isn't much value in having as many as the Lakers and Celtics do but this coming offseason it's possible that they will be helpful for the Celtics. They may go some amount under the cap but want to stay above it to retain the MLE instead of getting the smaller RME. Cap holds count against the cap but not the tax or apron so, while they won't need thirteen of them, they just sit there so it's not a big deal.

Crow wrote:Depending on how much you want to promote it, you might post it at various realgm forum sections, some of the more serious team blogs and other analytic blogs.

I never know how much I want to promote it because I suck at promoting anything but I did just post it in the "CBA / Business" section at RealGM. Thanks for the advice.

Really cool idea. Gonna mess around with this more when I get the time and then I'll give you some more feedback.

Hello everyone,

We've updated the Roster Builder tool and we'd very much appreciate it if you take a look at it. Even though we didn't get enough people to use it (which is understandable given the complexity of the stuff), it's still a hobby to us and we're keeping the project alive for another season. Dangercart has updated the tool itself a couple of days ago for the upcoming season and I've just changed the design of the website to give it a more modern look. We're looking to get some feedback to make the tool better and I hope you'll enjoy using it. If you have any problems with the tool or you want to give some feedback, please don't hesitate to do so.

Link to the tool: NBA Roster Builder — FAQ

Thank you.

I totally forgot about this. I am no marketing expert but to help I posted a link to your site on about 15 sbnation blogs. Maybe others can throw out a few too?

Crow wrote:I totally forgot about this. I am no marketing expert but to help I posted a link to your site on about 15 sbnation blogs. Maybe others can throw out a few too?

Thanks, Crow! We've tried to promote the tool as much as we can but considering what the tool/website is about, it's no wonder we don't have many users. People find it easier to speculate unrealistic trades rather than check whether trades they're proposing is possible or not. We shared the tool on /r/NBA, here and emailed couple of people who're known to be CBA experts and that was it. We have a few loyal users and that's enough to keep us (mostly dangercart) going. But thanks for the support!

The tool has been updated to reflect the recent trades and the draft picks.

roster-builder.com

Crow wrote:I totally forgot about this. I am no marketing expert but to help I posted a link to your site on about 15 sbnation blogs. Maybe others can throw out a few too?

Thanks, I appreciate it. I can't imagine it ever being a popular tool but it does seem to have more traction this season than last and I think this season's version looks and functions a little better. I just finished updating as much contract information for 2014-15 as I can and have been slowly tweaking some of the logic as I learn more about how people use it. Let me know if you have any suggestions or general feedback as it's impossible for me to think of and test everything so I usually make updates based on what the few users I know about are asking for or trying to work through.

Last year I put up a post on the Salary Cap board at RealGM and they removed it as spam and then when I asked why they told me "because it's spam." Hopefully the SBNation blogs won't see it the same way!

I didn't check back yet to find out.

RealGM might have seen it as competition. Oh well.

The tool has been updated to reflect recent roster changes. (LeBron, et al.)