If you’re going to engage in risk communication, defining risk should be one of your first steps. But it’s not quite as easy as you might expect.

There is no consensus about how to define the term risk, and numerous definitions have been proposed because of the fragmented nature of scientific literature on risk and risk communication.

According to the Oxford English Dictionary, risk is “a situation involving exposure to danger.” This is probably the definition that jumps first to most people’s minds.

As used in most health, safety, and environmental studies, risk is the probability of an adverse outcome. Risk is therefore inherent in virtually every action, even inaction.

The word risk also has a long history in economics. A risk is an occurrence that can have positive or negative consequences of varying magnitudes.

As noted by Covello and Merkhofer, the term risk is multidimensional. Risk is a measure of uncertainty involving the following:

• the chance or possibility of an adverse consequence or outcome from an occurrence

• the probability of exposure to the occurrence

• the timing of the occurrence

• the magnitude of adverse consequences or outcomes of the occurrence

In its most basic form, risk can be defined by the equation:

Risk = Probability x Magnitude

Risk v. Hazard

Confusion can arise between the terms risk and hazard, which are often used interchangeably. But from a technical point of view, they are different. A hazard is typically described as a source of risk. It is something that is dangerous. It is a situation that could cause loss or injury. A hazard is something that can go wrong.

The term hazard typically refers to a substance, action, or event that can cause loss, harm, or other adverse consequences.

By comparison, the term risk refers to the likelihood of loss, harm, or other adverse consequences from exposure to a hazard. This is what fundamentally distinguishes risk from hazard.

Risk is created by a hazard. For example, a toxic chemical that is a hazard to human health or an endangered species does not constitute a risk unless humans or endangered species are exposed to the hazard.

A hazard—be it radioactive, chemical, biological, mechanical, or otherwise—can pose a wide variety of risks to the living and nonliving environment. Since no analysis can address all possible risks of a given hazard, a key element in risk analysis is to explicitly identify the specific risk.

Pathway Prompt: Think of a hazard you encounter in your day-to-day life. What are the risks that arise from it? How would you best communicate that risk to a coworker? A family member? A stranger?

Communicating Effectively When Feelings, Fears, and Facts Collide

More information about risk, high-concern, and crisis communication can be found in Dr. Covello’s video-based course Pathway to Risk, High-Concern, and Crisis Communication. This master class introduces communicators to the tools and techniques for communicating effectively—while providing greater insight into why audiences react the way they do during times of stress.

The course comprises nine video lectures and accompanying text modules, plus supplemental materials for putting valuable lessons into practice.

More information about the course, including group rates and partnering opportunities, can be found by emailing info@pathwaycommunication.com.

Dr. Vincent Covello

Dr. Vincent Covello, director of the Center for Risk Communication, is one of the world’s leading experts and practitioners on risk, high-concern, and crisis communication. He is the author of more than 150 articles in scientific journals and the author/editor of more than 20 books. Dr. Covello is a consultant, writer, and teacher. He is a frequent keynote speaker and has conducted communication skills training for thousands.


Covello, V. T., & Merkhofer, M. (1993). Risk Assessment Methods: Approaches for Assessing Health and Environmental Risks. New York: Plenum Press.