More than 2,000 people who were falsely convicted of serious crimes have been exonerated in the United States in the past 23 years, according to a new archive compiled at two universities. There is no official record-keeping system for exonerations of convicted criminals in the country, so academics set one up. The new national registry, or database, is assembled by the University of Michigan Law School and the Center on Wrongful Convictions at Northwestern University School of Law.