Risk and uncertainty are central to many environmental and health stories, but they are often poorly reported.
Journalists who report on risks to human health or the environment must take care not to exaggerate or underplay the scale of any threat.
This may seem obvious, but risk is one of the hardest things to communicate accurately. This is partly because it can be very hard to actually determine what is a risk, and partly because public perceptions of risk can be very different from those of scientists and other experts who spend their days studying risk.
We know for instance that some chemicals are extremely dangerous to people if they are exposed at very high doses but can be harmless or even essential at low doses. Salt is an example.
We know also that what is harmful to animals may not be harmful to people. Aspirin kills cats but has improved the lives of millions of people as a painkiller and may also be beneficial for people with cardiovascular disease.
We know that some things – such as plane crashes – are very deadly but extremely unlikely.
To report accurately on risk a journalist must be able to understand statistics and be able to explain them in a way that is accurate and clear to their audience.
Journalists who fail to do this can create disproportionate fears or unrealistic hopes. They can also lose the trust of their audiences and discourage scientists from talking to the media for fear that their findings will be misinterpreted.
When reporting on a risk it is important to state what the risk is relative to. For instance, a study may conclude that exposure to a certain chemical will double the risk of a certain type of cancer.
This is a 100% increase and it sounds serious but if the cancer is extremely rare, affecting only one in every 10 million people, this means that the chemical could increase that risk so that one in every five million people could be affected – which overall is still a small risk.
People’s susceptibility to risk varies greatly so journalists should try to explain what other factors could heighten a risk, such as age, gender, genetics, existing health conditions or whether someone smokes.
It is important to report how a scientific study has reached its conclusions by saying, for example, how many people were studied, or whether the conclusions are based on research on animals such as laboratory rats rather than on data from people. Try to show how significant the evidence is and get the views of credible independent sources.
Individual studies often have contrasting findings. For example many studies show that drinking red wine can increase various health risks, but other studies reveal that for some people a certain amount of red wine could reduce some health risk. One study may find a risk but if hundreds of others find no risk. It is important therefore to put research findings in context of wider research.
To help make sense of risks, it can be useful to compare them to other well-known factors that people are more familiar with.
A comparison with the risk of dying in a road traffic accident can help to show the likelihood of a threat, while a comparison with the total number of people who die each year of all causes in a given place can help to show the scale of a threat.
When reporting on a scientific study, journalists should check whether the study has been funded by any organisation or company that has a vested interest (see Sources of Stories).
When reporting on risk journalists may also need to cover alternatives and solutions. If so, it is important to look beyond the immediate health or environmental concerns about a real or perceived risk, and focus also on the costs of action or inaction, in terms of other things that matter to society, such as jobs, or money. This kind of information helps people to make decisions about how to react in the face of a new risk.
It is important too to consider whether any proposed actions could have unintended consequences, such as policy changes that create new problems or medical interventions that carry additional risks of side effects.
The easiest way for a journalist to be sure that they understand a risk is to talk with the source of the information, such as the author of a scientific report. Reporters can also check whether they can effectively communicate the risk by asking colleagues to see if they understand it.
For a case study of risk reporting, this 4-page analysis [PDF] looks at how organisations and media outlets communicated about the risk of environmental health threats in Europe in 2004.
SciDev.Net – Communicating statistics and risk
Union of Concerned Scientists – Certainty vs. Uncertainty: Understanding scientific terms about climate change
Health in the News: Risk, reporting and media [PDF]
BBC – Editorial guidance on reporting risk [PDF]