How We Chose to Measure Risk

Risk is a tricky thing to think about, and how we chose to measure and communicate risk can make it even more challenging to comprehend. Our brains like to categorize things, and categorization is easiest when the categories are binary or represent three or fewer distinct possibilities. Once you start adding options and different possible outcomes, decisions quickly become overwhelmingly complex, and our minds have trouble sorting through the possibilities. In his book Thinking Fast and Slow, Daniel Kahneman discusses the challenges of thinking about risk, and highlights another level of complexity in thinking about risk: what measurements we are going to use to communicate and judge risk.

 

Humans are pretty good at estimating coin flips – that is to say that our brains do ok with binary 50-50 outcomes (although as Kahneman shows in his book this can still trip us up from time to time). Once we have to start thinking about complex statistics, like how many people will die from cancer caused by smoking if they smoke X number of packs of cigarettes per month for X number of years, our brains start to have trouble keeping up. However, there is an additional decision that needs to be layered on top statistics such as cigarette related death statistics before we can begin to understand them. That decision is how we are going to report the death statistics.  Will we chose to report deaths per thousand smokers? Will we chose to report the number of packs smoked for a number of years? Will we just chose to report deaths among all smokers, regardless as to whether they smoked one pack per month or one pack before lunch every day?

 

Kahneman writes, “the evaluation of the risk depends on the choice of a measure – with the obvious possibility that the choice may have been guided by a preference for one outcome or another.”

 

Political decisions cannot be escaped, even when we are trying to make objective and scientific statements about risk. If we want to convey that something is dangerous, we might chose to report overall death numbers across the country. Those death numbers might sound like a large number, even though they may represent a very small fraction of incidents. In our lives today, this may be done with COVID-19 deaths, voter fraud instances, or wildfire burn acreage. Our brains will have a hard time comprehending risk in each of these areas, and adding the complexity of how that risk is calculated, measured, and reported can make virtually impossible for any of us to comprehend risk. Clear and accurate risk reporting is vital for helping us understand important risks in our lives and in society, but the entire process can be derailed if we chose measures that don’t accurately reflect risk or that muddy the waters of exactly what the risk is.

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