The Department of Justice and the Federal Trade Commission announced on Tuesday that they will explore updating their horizontal merger guidelines, the first such change in 17 years.

Christine Varney, assistant attorney general for the Justice Department’s Antitrust Division, said the government would hold a series of public workshops to assess potential changes to the guidelines, which antitrust enforcers use to measure the competitive effects of proposed mergers. Varney, who spoke at a Georgetown Law Center symposium on antitrust law Tuesday, said the assessment would examine whether the current guidelines accurately reflect agency practice.