• Quality improvement
• Quality measurement
• Patient safety

Prospective clinical surveillance (PCS) is a safety measurement approach that fulfils many of the goals and principles of the latest thinking on measuring and improving safety.1 ,2 Compared with many current measurement practices, it may be more valid and reliable, with potential to facilitate learning and improvement and empower and draw upon the experience of front-line providers. It also has implications for external oversight of healthcare organisations.

In the study by Wong et al,3 PCS involved a trained nurse who visited a clinical unit on weekdays. The nurse looked for triggers indicating a possible adverse event by reviewing records of patients and talking to the front-line providers in the unit. The list of triggers used by the nurse was generated from prior research and input from providers in the unit, meaning that the triggers were customised for that unit. Trigger-positive records were then reviewed by an interprofessional team, which included front-line staff involved in the care, the trained observer and investigators. Providers were also encouraged to report additional events during this process.

In their 20-bed general medical ward in a tertiary care hospital, Wong et al found preventable harm in around 10% of patients. Adverse events included the usual suspects of adverse drug events, hospital acquired infections, falls, pressure ulcers and diagnostic errors. But other findings were perhaps more unexpected. Common categories of adverse events …