Duties and responsibilities

Expectations of physicians in practice

Overcoming bias in medical practice

Originally published December 2012

Like other healthcare providers, physicians may have conscious or unconscious biases that can affect the provision of care. Understanding and being aware of potential biases can help doctors to improve the care provided to patients, as well as reduce the medico-legal risks in their practices.

What are biases and prejudices?

A bias is a tendency or inclination that precludes consideration of an issue, or an inclination to favour a particular perspective at the expense of others. In clinical care, these biases (dispositions to respond) include reactions to stimuli or specific cues in the patient encounter. The term prejudice is often used to refer to preconceived, unfavourable attitudes towards a group sharing common characteristics.

Many different biases may influence decision making and diagnosis in medical practice. This article describes 2 important types:

  1. Affective biases (intrusion of the physician's feelings and emotions), including human rights-related prejudices
  2. Cognitive biases (distortions of thinking)


Both affective and cognitive biases can have potentially profound impacts on patient care. More often than not, physician biases are unconscious, 1 and individual doctors may not be aware of their own tendencies. Nevertheless, providing quality care to patients means doctors must attempt to recognize and eliminate their biases and prejudices.

Affective biases

It is increasingly recognized that a physician's unconscious emotional reactions to a patient or circumstance may interfere with achieving proper diagnosis and decision making. Examples in which patients are sometimes prejudged or their symptoms dismissed without sufficient evaluation include those patients with existing health conditions such as mental illness, alcohol and other substance abuse, obesity, certain communicable diseases, a history of noncompliance to treatments, or frequent previous visits perceived to be for trivial reasons. Individuals from different cultures or of certain sexual orientations or with poor socio-economic status may also trigger an affective bias.

Physicians can gain new insights and set aside personal biases and prejudices by learning more about specific issues or about patient groups. For example, physicians may decide to learn more about the health issues or risk factors among gay, lesbian, bisexual and transgender patients, new immigrants of a particular ethnicity, or patients who hold religious beliefs that may affect their healthcare choices and decisions. Continuing medical education on specific health issues common to a particular patient population may also be valuable.

Certain prejudices are clearly recognized as discriminatory in Canadian society and discrimination is prohibited by law. For example, discrimination against gender, race, age, disability, and sexual orientation is not permitted.

Beneficence and social justice — fundamental principles of medical practice — require doctors to work toward eliminating discrimination in healthcare and respecting patients' human rights. The CMPA advises physicians to take steps to minimize the risk of allegations of human rights violations. (See also the article "Ending the doctor-patient relationship".)

Cognitive biases in decision making and diagnosis

In recent years, research in cognitive psychology and medicine has identified the profound impact of cognitive biases on reasoning, decision making, and diagnosis. Cognitive biases are distortions of thinking. Common ones include anchoring (focusing on 1 symptom or diagnosis and failing to consider other possibilities), premature closure (uncritical acceptance of an initial diagnosis), and search satisfaction (calling off the search when just 1 abnormality has been found).

Another type of cognitive bias is availability bias. In this case, recent or vivid patient diagnoses are more easily brought to mind (i.e. are more available) and overemphasized in assessing the probability of a current diagnosis. In influenza season, for example, it is tempting to consider all patients with fever and myalgias as having influenza. This sometimes results in delays in diagnosis of patients with meningitis.

All of these biases can interfere with reaching a correct diagnosis or recommending appropriate treatment for patients. These biases can also be inter-related, and more than 1 bias can affect the diagnosis or management of a patient.

Research is ongoing to identify strategies for physicians to prevent cognitive biases.

Biases when providing opinions

Affective and cognitive biases may also come to the fore when providing retrospective opinions. Physicians may be asked to provide opinions on clinical events for quality improvement and peer accountability reviews, or as expert witnesses in court or for medical regulatory authorities (Colleges). Physicians may also provide opinions when preparing third-party medical reports, often on matters of unique sensitivity, for insurers, lawyers, or others on behalf of patients.

Hindsight bias or outcome bias exaggerates the predictability of an event after it has happened. Knowing an undesirable and unexpected clinical outcome has occurred increases the belief that it was predictable, therefore preventable and related to carelessness or poor clinical care. For doctors, outcome knowledge can bias thinking on the quality of the processes that led to the outcome.2 Hindsight bias is almost inevitable in retrospective reviews. Bias is increased when reviewers know there has been an adverse outcome, and the degree of bias is proportional to the severity of the outcome.3

Other biases may also affect retrospective opinions. For example, learned intuition bias refers to the phenomenon when a person has learned a complex process and it later seems intuitive. The person does not easily recall the difficulty he or she had when first trying to learn the process. When someone new to a process of care has difficulty with it, the problem often stems from poor system design, orientation, or training. Making improvements in these will benefit everyone.

When physicians agree to provide opinions or prepare expert reports, the CMPA recommends they provide opinion evidence that is fair, objective, non-partisan, and related only to matters within their area of expertise. Physicians can try to avoid hindsight and other biases by considering how factors such as the natural evolution of a disease, additional clinical information, and improvements in the technology used for clinical testing can affect retrospective assessments. Those with advanced knowledge in a specialty should be cautious on commenting on the care of those in other types of practice. Trying to understand the context of care and the rationale for decisions at the time of the care in question is important.

The CMPA is here to assist

Ultimately, physicians want to have trusting and respectful relationships with their patients and provide excellent patient care. Identifying and addressing biases aids in developing successful doctor-patient relationships, supports effective care delivery, and may help decrease medico-legal risks.

Members should contact the CMPA if they have questions or need assistance with this challenging aspect of practice. CMPA medical officers, physicians with extensive co-legal experience, will listen to members' concerns and provide advice.


  1. Moyer, C.S., "Doctors' unconscious racial biases leave patients dissatisfied," American Medical News (March 26, 2012). Retrieved on April 3 2012 from: http://www.ama-assn.org/amednews/2012/03/26/prsc0330.htm
  2. Henriksen, K., Kaplan, H., "Hindsight bias, outcome knowledge and adaptive learning," Quality and Safety in Health Care (2003) Vol. 12, supplemental issue 2 p.46–50
  3. Hugh, T.G., Tracy, G.D., "Hindsight bias in medicolegal expert reports," Medical Journal of Australia (2002) Vol. 176, no.6. p.277-278.

DISCLAIMER: The information contained in this learning material is for general educational purposes only and is not intended to provide specific professional medical or legal advice, nor to constitute a "standard of care" for Canadian healthcare professionals. The use of CMPA learning resources is subject to the foregoing as well as the CMPA's Terms of Use.