As a part time baseball sabermetrician in my spare time, and a Maverick fan full time, it always sparks my interest when someone makes an unsubstantiated claim in the media. Lately, everyone's been harping over the Mavs supposedly unique problem with holding large leads. The headlines recently proclaimed "Mavs blow lead of 17 or more for FIFTH TIME", as though no other team ever does it, much less multiple times.
As best I can tell, there is no repository of records of this type, but anecdotal information suggests that even good teams lose leads, and sometimes large ones at that. For example, the World Champion 2011 Mavericks blew a 23 point lead and lost to the Portland Trailblazers in game 4 in the first round of the playoffs. Several times that season, that same excellent team gave up large leads.
I therefore contend that while this team has some issues on the court, the blown leads is not anything to concentrate on specifically. It's just something that can happen in an NBA game. The idea, for a team to be good, is to keep it from happening very often, and not lose when it does.
The following article, from 2011, actually attempted to measure teams abilities to keep and hold leads: http://hangtime.blogs.nba.com/2011/01/20/how-you-finish-matters-most/ . The author makes a point that the best teams keep and hold leads the most. Of course, you have to be fairly decent to get a lead to begin with. I thought it was inconclusive, at best.
A better resource is the following statistical page I've discovered:
This site is a treasure-trove of obscure statistics, but this particular page measures largest average "biggest" leads per team (The Mavs are 10th in that category), and breaks it down by quarter. While the Mavs are a top-5 team in leads at the half, they are 19th in margin in the second half. You can come to your own conclusions, but based upon what I've seen on the court, the Mavs often appear tired in the second half of games, and these stats seem to back that up. Add in the propensity to lose leads late in games, and you can definitely see a trend.
If the Mavericks are to improve, they need to work on their second half performance. If this means a different mix of players on the court, or better conditioning, is a coaching issue. Their elite performance in the first half of games would equal a potential final-four performance if it could be equalized throughout games!
Some other examples of teams with issues along these lines: Minnesota, (2nd in 1st half, 13th in 2nd half margin); Houston (4th, 15th). Several teams are fairly consistent, but some good teams start off slow and finish strong: Indiana (15th, 1st); Portland (11th, 2nd); Toronto (13th, 7th).
I'd appreciate anyone's insights into this, as well as any research they've uncovered on their own.