The Chasm report identifies six attributes for a quality health care system: (1) safe, (2) effective, (3) patient centered, (4) timely, (5) efficient, and (6) equitable.¹ Safety is a preeminent feature of health care quality, first on the list, though not the only one. Health care quality may be thought of as a circle, with each of the six essential features forming smaller overlapping circles within the larger whole.

Over the past 60 years, many models have been developed to help organizations improve quality and enhance safety. Among the methodologies discussed here, we distinguish between tools that address all six aspects of quality versus tools with an explicit focus on safety and hazard analysis. General QI tools can be used to improve timeliness, efficiency, and other goals in addition to safety. PHA tools are more prescriptive and require more steps, including documentation; in cases where a tool is applied to an ongoing service operation (i.e., HACCP), it becomes a part of a firm’s daily functioning.² This distinction provides the framework for discussion in this paper of the various methodologies:

For comparative purposes, we also include discussion of Root Cause Analysis under PHA tools. Following is a brief outline of each approach, describing purpose and features, a thumbnail history, and key applications. Tables D–1 and D–2 summarize key points.

The three approaches we will describe can be used to improve all aspects of quality and are not targeted specifically at hazard prevention. Still,