In 2005, draft guidelines were published for reporting studies of quality improvement as the initial step in a consensus process for development of a more definitive version. The current article contains the revised version, which we refer to as Standards for QUality Improvement Reporting Excellence (SQUIRE). This narrative progress report summarizes the special features of improvement that are reflected in SQUIRE and describes major differences between SQUIRE and the initial draft guidelines. It also explains the development process, which included formulation of responses to informal feedback, written commentaries, and input from publication guideline developers; ongoing review of the literature on the epistemology of improvement and methods for evaluating complex social programs; and a meeting of stakeholders for critical review of the guidelines' content and wording, followed by commentary on sequential versions from an expert consultant group. Finally, the report discusses limitations of and unresolved questions about SQUIRE; ancillary supporting documents and alternative versions under development; and plans for dissemination, testing, and further development of SQUIRE.