Impact of repeated hospital accreditation surveys on quality and reliability, an 8-year interrupted time series analysis.

Objective: To evaluate whether hospital re-accreditation improves quality, patient safety and reliability over three accreditation cycles by testing the accreditation life cycle model on quality measures.

Design: The validity of the life cycle model was tested by calibrating interrupted time series (ITS) regression equations for 27 quality measures. The change in the variation of quality over the three accreditation cycles was evaluated using the Levene's test.