Clinical Reasoning Toolkit

How We Make Decisions

Learn more about the causes of errors in clinical reasoning and the key factors in making more mindful decisions.

From Mindless to Mindful Practice – Cognitive Bias and Medical Decision Making
Pat Croskerry
Addressing error is fraught territory; this article discusses why, and further encapsulates the taxonomy of Type 1 and Type 2 reasoning, as well as some examples of biases.


Achieving quality in clinical decision making: cognitive strategies and detection of bias
Pat Croskerry
This primer provides a description of 30 heuristics and biases in the context of Emergency Medicine. The reader learns biases ranging from the Gambler's Fallacy to Sutton's Slip in the service of improved patient care. Throughout the article, it is emphasized in a nonjudgmental manner that these are human flaws in cognition and require effective debiasing strategies.


CAEP Card with Biases
Two-page PDF document with a concise summary of 21 heuristics/biases.


Diagnostic Failure: A Cognitive and Affective Approach. In: Henriksen K, Battles JB, Marks ES, Lewin DI, editors
Pat Croskerry
Two major phenomena that may undermine rational thinking are cognitive dispositions to respond (CDRs) and affective dispositions to respond (ADRs) toward the patient. This report reviews key determinants and characteristics of the major CDRs and ADRs, and further describes a "cognitive and affective autopsy."


A universal model of diagnostic reasoning
Pat Croskerry
An engaging description of Croskerry's rationality-based approach to decision-making, including System 1 and System 2 decision-making, and the interactions between the systems.


The Causes of Errors in Clinical Reasoning: Cognitive Biases, Knowledge Deficits, and Dual Process Thinking
Geoffrey Norman, et al.
A counterpoint to dual process theory, this article reviews literature which suggests that both Type 1 and Type 2 processes contribute to errors, and that strategies directed at the recognition of bias are less effective than the reorganization of knowledge.


Conditions for Intuitive Expertise
Daniel Kahneman, et al.
Two renowned psychologists compare Naturalistic Decision Making (NDM) with Heuristics and Biases (HB) in a spirited discussion, sharing the pearls and pitfalls of each approach as they are applied to Dual Process Theory.


NSTEMI or Not?
J William Schleifer, et al.
An expert diagnostician reasons through a high-stakes scenario while the cognitive strategies involved are unveiled and explained. This is a useful demonstration of illness scripts, System 1 vs. System 2 thinking, and the utility of a mental “pre-mortem” examination.

Young Professionals Discussing Medicine
More from the Clinical Reasoning Toolkit
Assessment of Reasoning

Errors in clinical reasoning are central factors in many diagnostic errors. Use the Society to Improve Diagnosis in Medicine (SIDM)'s Assessment of Reasoning Tool to support you in evaluating your trainee’s clinical reasoning skills.