In 1980 Richard Peto explained to ordinary people the quantitative dangers of smoking:

“Among an average 1000 young men who smoke cigarettes regularly – about one will be murdered, about six will be killed on the roads, and about 250 will be killed before their time by tobacco.”

There are many good attributes to this explanation that can be followed when trying to communicate risk. The concept of risk acknowledges every course of action or inaction in clinical care may be associated with risks and/or benefits. Risk can be thought of as an unwanted outcome or as an uncertainty about the occurrence of that outcome. In defining risk we therefore can think of it as either an unwanted outcome and/or the probability of that unwanted outcome occurring.

Bogardus’ work highlights risk has five basic fundamental dimensions, and understanding these dimensions may help when trying to communicate risk more effectively:

1. Identity: Some risks may not even be known about and sometimes it may be hard to quantify whether the exposure is a risk or a benefit.
2. Permanence: Requires an understanding whether the risk is temporary or permanent and how long it will occur for. For example, if you have some numbness after a hip operation the question you want answered is: How long will it last for? Or, if I do get numbness, is it permanent?
3. Timing: When will the risk occur, does it occur early compared to late after a procedure - does an infection after an operation occur early just after the operation or later, like when I have left hospital?
4. Probability: Will it occur in all patients, how likely is it? If I get it once will I get it all the time?
5. Value: How important is the risk to the patient given his current ideals and lifestyle?

Ultimately what we want to know is "What is the best way to communicate to patients the chances of a ‘bad’ event occurring?" Although this is not exclusive to patients, we face risks every day about which we want better and more informed communication. For instance, as a parent you make decisions daily about what your children may or may not do based on risks about which we often want better information. In pondering why the uptake of the current swine flu vaccine is proving so controversial, does the current debate provide adequate information on the benefits and risks?

When deciding about the pros and cons of a given risk the fifth and perhaps most important dimension of risk is therefore its value, its subjective “badness”. Some people, no matter how small the risk – for example flying – may perceive the subjective badness to be so impelling that no matter how well you communicate the quantitative aspects of the risk, which are incredibly small when it comes to flying, they still won’t fly. Although, most clinicians make amiable attempts to quantify the amount of risk, the ultimate determination of importance is its level of subjectiveness. In effect the first four dimensions of risk identity, permanence, timing, and probability are there to help determine our own personal value to be associated with the risk. These dimensions should be thought of at the outset when communicating risk whether verbal or written.

The next time you see an article outlining risk see to what extent the dimensions have been incorporated into the communication, and in the next articles on this series we will consider the expression of risk, both qualitatively and quantitatively.