• Primary care
• Quality improvement
• Quality measurement

Upon reading Dr Young's letter,1 we felt we should have prefaced our article by quoting Box and Draper who wrote in their classic 1987 book,2 ‘all models are wrong, but some are useful’. Our goal in developing a new model for safer diagnosis in healthcare was to illustrate the myriad, complex, socio-technical issues and their interactions within a complex adaptive healthcare system that must be considered when attempting to define and measure errors in the diagnostic process.3 While the comments by Dr Young provide one clinician's view of the complexity and breadth of diagnostic error, we welcome an opportunity to respond to clarify the premise of the Safer Dx framework. Dr Young is concerned that we presented the problem of diagnostic error as black and white rather than considering day-to-day realities of patient care that includes vast uncertainties in data collection, interpretation and synthesis. He further asserts that the concept of delayed diagnosis in primary care needs to be severely curtailed and that except for straightforward cases of blatant negligence we should not even use the language of delayed or missed diagnoses. Lastly, he writes that physicians might be vilified for missed or delayed diagnosis even though they made appropriate and informed decisions including watchful waiting when the diagnosis was not yet clear. In our response below, we attempt to lay many of these concerns to rest and provide further information on diagnostic error reduction research. We believe the concepts that we clarify herein will reassure hardworking primary care clinicians on the frontlines that the major goal of our framework is to promote the understanding and reduction of preventable diagnostic harm to our patients and not assign blame. Moreover, the rationale for the framework and our response applies to all clinicians, not just those in primary care. …