The Securities and Exchange Commission has made progress in tightening its procedures for managing its caseload of enforcement investigations but internal communications and use of resources still must be improved, congressional auditors have concluded in a new report.

The workings of the SEC’s enforcement division have come under intense congressional scrutiny after revelations in December that the agency failed to detect the massive Ponzi scheme run by money manager Bernard Madoff, despite red flags raised to its staff by outsiders over the course of a decade.