Uncertainty Over Whether N.F.L. Settlement’s Money Will Last

As intriguing football matchups go, Sunday’s Super Bowl has nothing on one looming down the turnpike in federal court in Philadelphia — with Judge Anita B. Brody the ultimate referee.

Brody, considering the N.F.L.’s recent settlement with 4,500 retirees over work-related brain injuries, has asked both sides to demonstrate that their $765 million bargain will fulfill its promise to compensate every currently retired player who has or will develop a neurological condition such as dementia or Parkinson’s disease.

Lawyers for the plaintiffs and the N.F.L. said independent actuaries and medical experts had endorsed the terms of the settlement. But the lawyers refuse to share any of their data with the public to help substantiate how they arrived at the $765 million figure, and there is growing displeasure among plaintiffs who have not been allowed to see the data, either.

Numbers can speak for themselves, though, and they bring a clear warning: The $765 million could run out faster than either side apparently believes. When one forecasts how many of the roughly 13,500 currently retired players may develop these conditions over the next 65 years, compensating them as the settlement directs could very well require close to $1 billion, and perhaps more.

No one can divine how many players will develop these conditions. But the best data available comes straight from the N.F.L., and it becomes instructive after some basic guidelines.

The settlement essentially…