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Risk Communication: An Overview

I Introduction

The process of risk communication begins with a hazard or danger (actual or potential) and an assessment of that hazard. "Usually by law, but sometimes by commitment"(1), some organization or group is responsible for managing the communication related to the hazard--a critical process designed to avoid or minimize fear and hostility, engage the public in the risk-management decision-making process and/or enable the public to take actions to reduce their personal risk. One well-accepted way of defining the risk-communication process is "an interactive process of exchange of information and opinions among individuals, groups, and institutions concerning a risk to human health or the environment"(2).

The risk-communication process may involve many types of messages and processes. It might include, for example, newspaper articles discussing the chance of falling victim to a violent crime, a doctor explaining the chance of birth defects to prospective parents, emergency-response workers trying to evacuate an area as a severe storm approaches or posters warning smokers about lung cancer. It may also be applied to topics such as automobile safety, HIV/AIDS, hazardous chemical waste sites, use of cell phones, medical procedures, and restaurant food safety.

Though it sounds like a straightforward concept, it is in fact filled with challenges. Even when the risk or danger is well understood (which is often not the case), many complex factors affect how audiences react when presented with risk information. The public's response to risk- communication efforts depends not solely on facts and technical information, but also on their existing knowledge, values, beliefs, emotions and whether they feel the people communicating about and/or managing the risk are trustworthy and credible.

Other risk communication hurdles include translating technical terms into meaningful language and choosing the best communication methods to reach the intended audience (considering factors such as literacy level, suitable graphics, appropriate tone).

Even with a thorough understanding of the audience and how to most effectively present information, risk communication is complex. For example, knowing that values and emotions affect not only the audience receiving the communication but also those sending it, how can the public be certain of the accuracy or objectivity of the message? There are other questions, too, such as what amount of information release or persuasion is ethical?

As you can see, the risk-communication process requires many types of expertise. Though we do not have sufficient space to address all the areas in detail in this bulletin, a more detailed discussion is available in the September 2000 edition of THCU's newsletter, and an extensive list of additional resources is provided at the end of this article in in OHPE 168.2.

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II Planning

Whether you are reacting to an urgent risk situation, preparing (to the degree possible) for a possible crisis or working to address a less dramatic but ongoing hazard (cigarette smoking, air pollution, use of certain pesticides, etc.), a good plan is essential. A formal, written plan can help set priorities, is more likely to get management and other stakeholder support, and can back you up if your approach is challenged. Risk-communication planning is similar in many ways to planning for any other kind of health communication.

A risk communication plan should include

* Background on the risk (e.g., the nature of the hazard, who or what will be harmed and how)

* Information about the laws or mandates guiding the risk-communication effort

* The purpose and objectives of the risk-communication effort (e.g., to change a behaviour, reduce fear, raise awareness)

* A profile of the target audience(s) (e.g., their previous experience with the risk, education level, concerns or feelings)

* An outline of the risk-communication strategies and messages to be used

* A description of the evaluation plan

* A detailed time-line that identifies tasks and people responsible for completing them

* A budget

* Formal sign-off from all relevant planning staff and management

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III Message Development

Risk communication strategies may focus on education, motivation or consensus building, but the point is always to help the public (or a specific audience) make a decision about the risk. Messages designed to do this may be delivered to the public via the news media (tv, newspapers, radio), technical reports, posters, ads, forums, displays, computer applications, face-to-face, newsletters, professional organizations, community service agencies, etc., and each medium has its advantages and limitations. For example, television reaches many people but needs visual material and is typically presented in short segments, and newspapers rely on the written word and can present longer, more complex messages but are less vivid and immediate in emotional impact (3). The characteristics of each channel affect the type of message that can be effectively transmitted (4).

The risk-communication messages themselves may include verbal statements, pictures, advertisements, legal briefs, warning signs or other types of information materials. In general, the most effective risk-communication messages are those that come from a credible and trustworthy source; are presented in multiple formats; are within an honest, open strategy; and are carefully tailored to the intended audience(s).

At a minimum, a risk-communication strategy should include information on

* the nature of the hazard;

* the probability of exposure to the hazard (for the total population and specific segments of the population if they differ);

* the probability of harm from a given (and multiple) exposure to the hazard;

* how the hazard interacts with exposure to other hazards;

* practical, risk-reducing actions or alternatives that affected people can take (with information on their effectiveness, costs and benefits);

* the benefits that might be given up if the risk were reduced or eliminated (and who would get and/or lose the benefits);

* any uncertainties about risks and benefits (including data gaps, areas of significant disagreement among experts, assumptions on which estimates are based and levels of confidence about probabilities);

* who is responsible for risk-communication and risk-management decisions; and

* the limits of the communication, defined by laws, policies, etc. (i.e., don't promise information or actions that you will not be able to deliver).

Unfortunately, in practice communicating this information to the appropriate people is rarely easy and can be extremely controversial, particularly when the hazard being described is itself the center of controversy. Often risk communication is necessary in a crisis situation and/or when there is still enough scientific uncertainty to allow different experts to draw contradictory conclusions. Even when the risk is fairly well understood in the scientific community, it can be difficult to present the information to the public in a way that is accurate, complete, engaging, non-manipulative and helps the intended audience make an informed decision. Stakeholder biases can further complicate the process, since the beliefs and interests of risk communicators and the organizations they represent can slant or even completely misrepresent information. Though in most situations it is not possible to overcome all of these difficulties, the following tips can help improve most risk-communication efforts.

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IV Tips for Improvement

1. Respond as completely as possible to audience biases, misconceptions, feelings, concerns and needs surrounding the risk

It is extremely important to gather as much information as possible about the people (audiences) that could be affected by the risk. This audience analysis information should be used to guide the message-development process because audience responses to risk are never based solely on technical information or statistics. Many other factors affect audience reactions to risk messages and should be taken into account when making risk-communication and management decisions.

When people consider their options, for example, they are often influenced by an optimistic bias or an unrealistic perception that they are not at risk, or are at a greatly reduced risk for a particular threat (5,6,7,8,9,10,11,12). When this is the case, risk communication efforts should focus on personal susceptibility and responsibility. Other misconceptions should also be addressed by filling in knowledge gaps.

When the audience is hostile, apathetic or feels like a victim, risk-communication efforts should openly acknowledge their concerns and feelings, emphasize past successes and provide as many choices as possible. When feasible, it can also be worthwhile to open the risk-assessment and management process to stakeholder participation.

2. Whenever possible, use language and concepts that the intended audience(s) already understand(s).

Risk messages should not contain acronyms, abbreviations, scientific notation, or mathematical formulas or exponents. Research has even shown that seemingly familiar terms, such as precipitation forecasts, are often misunderstood. In studies by Murphy et al. (13,14) people were equally likely to interpret a "70% chance of rain" as "rain 70% of the time," "rain over 70% of the area" and "70% chance of some measurable rain" (the official definition). When it is not possible to use familiar terms, be careful not to omit important information just because it may be difficult to explain. Instead, provide clear definitions with unfamiliar terms or concepts.

3. Use magnitudes common in ordinary experience.

Most people have difficulty comprehending magnitudes that are exceedingly small or exceedingly large. Sometimes analogies can help convey such magnitudes. "For example, a risk of 0.05 may not mean much to most people but the statement that about 5 people in an auditorium of 100 people would be affected is much easier to comprehend.

4. When applicable, emphasize cumulative probability over extended periods of time instead of one-shot probabilities.

Most people have difficulty distinguishing between cumulative and one-shot probabilities. For example, Linville and colleagues (15,16) found that college students tended to over-estimate the probability of infection with HIV from a single unprotected exposure and to underestimate the probability of infection from repeated unprotected exposure. This means that if risk communicators only talk about the probability of infection from a single unprotected sexual encounter, they risk miscommunicating by leaving the calculation of cumulative probability to the audience. Cumulative probabilities convey the higher probability associated with long-term risk, and may be more likely to motivate behaviour change (17).

5. Instead of expressing probabilities in quantitative (numeric) terms, try to use a qualitative tem that is close in meaning (if a tested term is available).

Though quantitative terms are obviously more precise, most people are more likely to use and understand qualitative expressions. For instance, a person might say that it is "very likely" that they will buy a new sofa this year, but it would be unusual for them to say that there is a .90 probability they will do so (18). For example, Kassler et al. (19) found that a .88 positive predictive value for a rapid HIV test could be more easily understood by clients if expressed as "probably infected," "very likely infected," "highly likely to be infected" or "very good chance of being infected."

6. Stick to informing an audience unless influencing techniques have been deemed appropriate following a legitimate scientific and public process.

Attempts to persuade audiences may be viewed as unethical and with hostility, particularly when

* there is unresolved controversy over an issue;

* the techniques used to influence approach or include outright deception; and

* the risk is confined largely to the person undertaking a particular behaviour and does not put others at risk (e.g., lifestyle issues such as a consistent diet of high-fat foods may be viewed as a risky behaviour that only affects the individual eating the high-fat diet).

Emotional appeals (such as fear, tragedy, or humour) fall into the category of influential communication and should be used with caution, as the conditions under which people view these as acceptable and under which they are effective are not well understood.

Even subjective words such as "significant," "negligible" and "minor" can be inappropriately biased, as they beg the questions "significant to whom?" "under what conditions?" and "based on what evidence?"

7. Be conscious about how different ways of describing risks reflect different values and can be misleading or manipulative.

Choice of measure can affect how risk a hazard appears. Consider the following ways in which annual fatalities resulting from emission of an air toxin might be presented (20):

* deaths per million people in the population,

* deaths per million people within miles of the facility,

* deaths per facility,

* deaths per ton of the airborne toxic substance released,

* deaths per ton of chemical produced, and

* deaths per million dollars of product produced.

There are even more ways to summarize deaths, each embodying its own set of values. "For example, 'reduction in life expectancy' treats deaths of young people as more important than deaths of older people, who have less life expectancy to lose. Simply counting fatalities treats deaths of the old and young as equivalent. Using 'number of deaths' as the summary indicator of risk implies that it is equally important to prevent deaths of people who engage in an activity by choice and deaths of those who bear its effects unwillingly. It also implies that it is equally important to protect people who have been benefitting from a risky activity or technology and those who get no benefit from it"(21).

Different ways of presenting the same measure can also create different impressions. For example, a study found that a vaccine that reduces the probability of contracting a disease from 0.2 to 0.1 is less attractive to people if it is described as effective in half the cases than if it is presented as fully effective against one of two virus strains (22).

8. Use caution when comparing risks.

Comparing risks, for example one that is familiar to one that is unfamiliar, can help audiences understand probabilities and make decisions about appropriate action. Establishing effective and ethical comparisons, however, can be a tricky process that warrants extreme caution. A risk comparison could, for example, mislead someone into thinking that if they are willing to take the larger of the two risks, they should accept the smaller one as well (23,24). In general, only risks with similar characteristics (outcomes, controllability, level of public outrage/concern about the risk, etc.) should be compared, otherwise the comparison will be confusing to the audience.

9. Whenever possible, use clear visuals to accompany or replace other forms of communication.

Carefully chosen (or developed) visuals can make "information transmission more rapid, realistic and accurate than is possible in purely verbal messages" (25). Visuals such as photos, pictures, illustrations, graphs, charts, tables and labels can help clarify abstract concepts, improve comprehension and recall and help put facts into context. They are particularly useful for

* audiences with low literacy or education levels;

* raising awareness about a previously unknown risk;

* portraying conditions that indicate a risk, such as a blocked fire door;

* showing the potential effects of a risk that can be seen, such as a visible health effect or an effect on plants;

* depicting size of, significance of and changes in level of risk over time;

* comparing probabilities of a given risk occurring in different situations or for different groups of the audience; and

* comparing various options and alternatives (please refer to above section on comparing risks for more information).

The key to effective visuals is being clear and not manipulative and tailoring the design and content to the needs of the audience so that they are better able to make an informed decision about the risk. This can involve using different visuals for different segments of the intended audience (consider, for example, the types of visuals that would be appropriate and engaging for a Canadian trained doctor versus a non English-speaking, recently-emigrated parent) and always involves pretesting materials with the intended audience (see below).

10. Test all messages with members of the intended audience.

Regardless of how closely the above guidelines have been followed, it is of the utmost importance to test messages with members of the intended audience before they are widely distributed. At a minimum members of the intended audiences should be asked if they

* are interested in the message,

* feel that the message is relevant to them,

* can understand the message (get specific details on how they interpret the message),

* think it is biased or distorted in any way, and

* feel the message provides enough information to help them make the best decision.

If resources are available, it is also wise to consider having messages reviewed by independent experts in the field of the applicable risk and/or the general area of risk communication.

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V Evaluation

It is mistaken to expect good risk communication to always reduce conflict, maximize general welfare and smooth risk-management, since risk-management decisions that benefit some can harm others. Good risk communication can only be expected to raise the level of understanding of relevant issues or actions for those involved and satisfy them that they are adequately informed within the limits of available knowledge But even though good risk communication cannot always be expected to make a situation or decision easier, poor risk communication will nearly always make it worse (26).

Some sample risk communication indicators include (27)

* Have all members of the audience been alerted to the risk?

* Was consistent information given regarding the risk?

* Does the audience understand the risk well enough to make decisions?

* Did the audience change to less risky behaviour?

* Were all segments of the audience represented in building a consensus?

* Was a consensus reached?

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VI Final Thoughts

This quick overview is just enough to raise awareness about the complex nature of health risk communication. For a more detailed discussion, check out THCU's newsletter on this topic, available at, as well as the excellent resources cited below or in OHPE 168.2.

VII References

1. Lundren, R., and McMakin, A., eds. 1998. Risk Communication: A Handbook for Communicating Environmental, Safety, and Health Risks. Columbus, Ohio: Battell Press. 2nd edition.

2. National Resource Council. 1989. Improving Risk Communication. Washington, DC: National Academy Press.

3. Lundren, R., & McMakin, A., eds. 1998.

4. Lundren, R & McMakin, A., eds. 1998.

5. Holtgrave, D.R., Tinsley, B.J. and Kay L.S. 1994. Heuristics, biases and environmental health risk analysis. In Applications of heuristics and biases in social issues. Vol 3. Social psychological applications in social Issues. Ed. L Heath, et al. New York: Plenum.

6. Kaplan, F.J. and Shayne, V.T. 1993. Unsafe sex: decision-making biases and heuristics. AIDS Educ. Prevent., 5:294-301.

7. Van der Velde, F.W., Hooykaas, C. and Van der Pligt, J. 1992. Risk perception and behaviour: pessimism, realism and optimism about AIDS-related health behaviour. Psychol. Health 6: 23-28.

8. Weinstein, N.D. Ed. 1987. Taking care: Understanding and encouraging self-protective behaviour. Cambridge, England: Cambridge Univ. Press.

9. Weinstein, N.D. 1988. The precaution adoption process. Health Psychol. 7: 355-86.

10. Weinstein, N.D. 1989. Optimistic biases about personal risk. Science 246: 1232-33.

11. Weinstein, N.D. Klotz, M.L. and Sandman, P.M. 1987. Public response to the risk from radon. 1986. New Brunswick, New Jersey: Rutgers University, Environmental Communication Research Program.

12. Weinstein, N. and Sandman, P.M. 1992. A model of the precaution adoption process: evidence from home radon testing. Health Psychol. 11: 170-80.

13. Murphy, A.H., and Brown, B.G. 1983. Forecast terminology: Composition and interpretation of public weather forecasts. Bulletin of the American Meteorological Society 64: 13-22.

14. Murphy, A.H., and Winkler, R.L. 1984. Probability of precipitation forecasts. Journal of the American Statistical Association 79: 391-400.

15. Fischhoff, B. 1989. Making decisions about AIDS. In Primary prevention of AIDS, Ed. Mays, V.M., Albee, G. W. and Schneider, S.F. Newbury Park, california: Sage.

16. Fischhoff, B., Bostrom, A. and Quadrel, J.M. 1993. Risk perception and communication. Annual Review of Public Health 14: 183-203.

17. Maibach, E. and Holtgrave, D.R. 1995. Advances in public health communication. Annual Review of Public Health 16: 219-38.

18. Maibach, E. And D.R. Holtgrave. 1995

19. Kassler, E.J., et al. 1994. HIV prevention counseling using an on-site, rapid HIV assay. Paper accepted for presentation at 10th Int. Conf. AIDS, Yokohama, Japan.

20. Covello, V.T., Sandman, P.M. and Slovic, P. 1988. Risk communication, risk statistics and risk comparisons: A manual for plant managers. Washington, D.C.: Chemical Manufacturers Association.

21. National Research Council. 1989. Improving Risk Communication. Washington, D.C.: National Academy Press.

22. Tversky, A., and Kahneman, D. 1981. The framing of decisions and the psychology of choice. Science 211 (4481): 453-458.

23. Covello, V.T., Sandman, P.M. and Slovic, P. 1988.

24. Fischhoff, B., Slovic, P. and Lichtenstein, S. 1981. Lay foibles and expert fables in judgments about risk. In Progress in Resource Management and Environmental Planning, T. O'Riordan and R.K. Turner, eds. New York: John Wiley & Sons.

25. Graber, D. 1990. Seeing is remembering: How visuals contribute to learning from television news. Journal of Communication 40: 134-155.

26. National Resource Council. 1989.

27. Lundren, R and McMakin, A., eds. 1998. Risk Communication: A Handbook for Communicating Environmental, Safety and Health Risks. Columbus, Ohio: Battell Press.