When settings outside the hospital are taken into account (ED, primary care), the overall number must be considerably higher. While many factors contribute to diagnostic failure, a variety of sources suggest that physician’s thinking has a lot to do with it.
Dual Process Theory describes how the brain makes decisions in one of two modes: through fast, unconscious, intuitive processes (System 1) or through slower, conscious, analytical processes (System 2). Mental short-cuts (heuristics) and biases are predominantly located in the intuitive mode where we spend most of our conscious time, and this is where the majority of decision failures occur. Thinking straight essentially means achieving a good balance between System 1 and System 2 decision making, and much of our cognitive effort needs to go into monitoring what our unconscious brains are doing in System 1. This is referred to by a variety of terms: metacognition, reflection, mindfulness, and others. They all involve cognitive de-coupling from System 1 and characterize the process of cognitive de-biasing. This is not easily accomplished in the ED or any environment where decision density is often high, throughput pressure exists, resources may be limited, and where decision makers may be fatigued and/or sleep deprived.
While medicine has acquired a variety of strategies over the years for de-biasing clinicians, added benefits can be obtained by developing specific mindware to tackle particular biases. Clinicians need to be aware of the operating characteristics of the dual process model of decision making, of the prevalence and nature of biases, and of how to apply and sustain de-biasing mindware in their decision making.