* Comcast accused of monopolizing Philadelphia cable TV market
* Lower court allowed customers to pursue class-action
* Supreme Court decision likely in 2012-2013 term
By Jonathan Stempel
WASHINGTON, June 25 (Reuters) - The U.S. Supreme Court agreed to review Comcast Corp's appeal of a ruling that let cable TV subscribers in the Philadelphia area sue as a group over alleged overcharges stemming from an effort to monopolize that market.
In a brief order on Monday, the nation's highest court said it will consider whether a trial court may certify a case as a class-action without first determining whether plaintiffs have introduced admissible evidence, including expert testimony, to justify awarding damages to the class as a whole.
Comcast, the largest U.S. cable company, had argued that the subscribers, who live in Pennsylvania, New Jersey and Delaware, did not have enough in common to sue as a group.
Class-action lawsuits can help plaintiffs recover more money and save on legal costs by not forcing them to sue individually.
The Supreme Court in its 2010-2011 term narrowed the ability of various plaintiffs to bring such lawsuits, in separate unrelated rulings involving AT&T Inc and Wal-Mart Stores Inc.
In the Comcast case, which was first brought in 2003, several subscribers accused the Philadelphia-based company of amassing a dominant position through a strategy, begun five years earlier, of buying rivals or swapping coverage areas, resulting in a "clustering" of services.
They said this allowed Comcast to triple its market share in the Philadelphia area, which peaked at 77.8 percent in 2002, and charge excessive prices, violating federal antitrust law.
In a decision last August, a panel of the 3rd U.S. Circuit Court of Appeals in Philadelphia ruled a trial judge had discretion to decide whether the plaintiffs would eventually be able to establish a common methodology to quantify damages, and that antitrust violations led to higher class-wide costs.
It said that to require more would essentially turn judges into juries, and "runs dangerously close to stepping on the toes of the Seventh Amendment by preempting the jury's factual findings with our own."
The Supreme Court is expected to hear arguments and decide the Comcast case in its next term, which begins in October.
The case is Comcast Corp et al v. Behrend et al, U.S. Supreme Court, No. 11-864.