Which statement best defines confirmation bias in clinical decision-making?

• A. An inclination to look for confirming evidence to support a diagnosis rather than look for disconfirming evidence
• B. A tendency to rely solely on imaging results for diagnosis
• C. A habit of asking patients to confirm their symptoms verbally
• D. A bias toward considering only rare diseases

Answer: (A)

Confirmation bias in clinical decision-making is the tendency to seek out and favor information that supports your initial hypothesis about a diagnosis, while downplaying or ignoring evidence that could contradict it. This leads you to look for data that confirms what you already think and to interpret ambiguous findings in a way that fits the assumed diagnosis.

This is best captured by describing an inclination to look for confirming evidence rather than disconfirming evidence. In practice, it shows up when a clinician anchors on an initial impression, selectively gathers or interprets tests and history to fit that impression, and pays less attention to findings that might point to another diagnosis.

To counteract it, clinicians can deliberately search for disconfirming evidence, maintain a broad differential, use structured checklists or diagnostic schemas, and seek second opinions or reflective practice to reassess hypotheses as new information becomes available.

Other options describe different issues: relying solely on imaging results emphasizes a data-source bias rather than a reasoning bias; asking patients to confirm symptoms is a communication step, not a bias in thinking; and focusing on rare diseases reflects a bias toward rarity rather than a tendency to confirm what’s already suspected.