Lawyers appointed to represent federal defendants who can’t afford an attorney sometimes have trouble securing expert witnesses, wading through voluminous e-discovery and persuading judges to approve their expenses, according to testimony at a public hearing Monday and Tuesday in Miami.

The Criminal Justice Act, which provides a system for compensating those attorneys, is under a two-year review by a committee appointed by U.S. Supreme Court Chief Justice John Roberts. The committee’s stop at the Wilkie D. Ferguson Jr. U.S. Courthouse was the second of seven hearings in cities from Portland, Oregon, to Philadelphia.