Lawyers for the plaintiffs alleging price-fixing among major makers of drywall will have to divulge the facts that support their claims while discovery is ongoing, the federal judge handling the multidistrict litigation has ruled.

U.S. District Senior Judge Michael M. Baylson of the Eastern District of Pennsylvania said that since information disclosed during discovery is electronically stored information, or ESI, he would grant the defendants’ motion to compel specific identification of key materials backing the plaintiffs’ claim.