It seems the news stories appear almost daily – this substance or that is shown to increase the risk of cancer; this substance or that is shown to delay the onset of Alzheimer’s disease; some unhealthy substance is found in the food we eat. No doubt it is all good and important information but for those untrained in assessing research data, such stories can result in more questions than answers: Should I stop eating this food? Should I start taking this or that substance? If my cancer risk is already negligible, how does the increased risk detailed in the news reports impact me? Should I be worried?

All valid questions, according to Michael Mehta, associate professor in sociology, who has spent the better part of his academic career studying risk and who admittedly “can’t help seeing risk in everything”. And he’s not alone. Society has become sensitized to risk, he said, “and it has a huge impact on decision-making at all levels”. In fact, he describes risk as “the new commodity of the 21st century – instead of wealth accumulation, we’re looking at risk avoidance”.

But for lay people grappling with how to react and respond to a dizzying array of studies and data, Mehta believes it’s important to understand that there is a distinct difference between how scientists and the public assess risk.

“The assumption is that risk is a scientific calculation of hazard, probability times consequence, but there are lots of ways scientists calculate risk,” he said. At one end of the scale is high probability risk with low consequences. An example of this is shovelling snow – the probability of injury (a pulled muscle, a fall) is high but the consequences are not severe for society. At the other end is low probability with high consequences. Mehta points to the small chance of an accident at a nuclear power plant, but the dire consequences of such an event. “Then there’s a range of risks that fall somewhere in between.”

Research has shown that the public tends to overestimate low probability/high consequence risk, he said. “We tend to worry about things that are very unlikely” such as a pesticide spill or an airplane falling from the sky. Scientists, however, do the opposite, overestimating high probability/low consequence risk. This is because they “tend to look at the data and rely on their own expertise to control the risk”.

The public also brings cultural, social and experiential values into risk assessment, he said. Consuming ground beef, for instance, carries with it a host of risks – E. coli, high cholesterol and a theoretical risk of mad cow disease. While scientists look strictly at the data relating to the risk of eating ground beef, “if a member of the public knows someone who got food poisoning, that tends to weigh more heavily on their minds than the actuarial data”.

Aside from the role personal or cultural experiences play in assessing risk, Mehta said there are two other ways of interpreting data. The first is to look at relative risk. Again using the ground beef example, he said this would involve weighing the risk of eating a hamburger against the risk of contracting salmonella from chicken.

Assessing relative risk is a process people use all the time by “placing all risk on a continuum to see where it lies relative to other risks”. That continuum might go from “the risk of smoking at one end to the risk of a meteorite falling on your head at the other”. He added that studies of how people perceive relative risk have shown “that we’re pretty sophisticated risk-processors”.

The second way of interpreting data involves the risk/benefit trade-off which “is more in line with how individuals process risk”. Using this method, “people trade off risk based on various factors like the rewards of engaging in a particular activity. There’s no doubt, for example, that driving a car is risky but we trade off that risk for the convenience. Recent reports about farmed salmon containing PCBs are another example good example. We know that salmon is good for you but if you avoid eating it because of a fear of PCBs, than you’re trading off the benefits to reduce the risk but you may be giving away benefits higher than the risk. We do this kind of thing all the time. It’s a natural way that most of us interpret risk in our lives.”

Risk is processed at all levels in society, Mehta said, from the macro-level where structures like Health Canada make decisions for all of society based on population-wide scientific data, to the micro or personal level of people making their own choices. The problem, however, “lies in the difference between the macro and micro levels, and here, individuals have to exercise what I call personal risk management.

“In making a risk decision, a person has to have information to draw on but if you’re looking just at what the scientists are telling us, that’s population-based and there are huge variations in the population. Instead, we need to consider our own personal information” like medical history that points to risk factors for diseases like cancer. “We have to know the scientific information and know our personal information and be able to make that link between the two. It’s not easy, but it’s something we have to do.”

For the lay person, interpreting scientific data is helped in part by what Mehta sees as the competent job being done by the media in placing the data in a context that includes cultural and economic factors. The result is that, “overall, because the media provides many different perspectives, people can get a pretty good feel for the risk debate, but scientists don’t. They think of risk strictly in terms of numbers ... but there’s no such thing as clean data.”

Leaving the scientists and their numbers, Mehta has some advice for non-scientific folk about dealing with risk. Number 1 – don’t react immediately. “There will always be an alternative explanation to any study,” he said. “If, however, you wish to avoid whatever is being studied, and there is an alternative available, and there are no consequences, then switch to that different product or food.”

His second piece of advice is to realize that risks and benefits are intrinsically linked – “recognize that to reduce risk you may be reducing benefits as well”. And finally, “remember about the relative risk example. Compare one risk to another, decide how much risk you can tolerate, and make your decision accordingly.”

For more information, contact communications.office@usask.ca

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