Conventional wisdom holds that access to legal representation increases the chances of securing a favorable outcome.

Harvard Law School professor James Greiner and statistics graduate student Cassandra Wolos Pattanayak teamed up three years ago to test that assumption through a rigorous methodological study involving people fighting for unemployment benefits. They arrived at a surprising conclusion: Bringing in a lawyer made no difference to the claimant’s odds of victory and could even harm his or her interests by delaying the process.