What is Risk, Really?

In public health, we talk about risk all the time, but it’s not always clear what that really means.

Risk isn’t just about how likely something is to happen, and it’s not just about how serious it would be if it did.  It’s a combination of both.

Take rabies as an example.  The likelihood of someone getting rabies from a dog bite in Canada is extremely low, but because rabies is almost always fatal once symptoms appear, the severity is so high that we treat every potential exposure as a high-risk situation.

Even when the chance of harm is low, the consequences are so serious that we take immediate action.

Now think about norovirus in a child care centre.  Norovirus usually causes a short-term illness which is not life-threatening for most people.  But it spreads extremely easily, especially in settings where children can’t manage hygiene on their own.

In this case, the likelihood of transmission is so high that even a mild illness becomes a serious risk when the whole centre is affected.

Good public health decisions (and strong oral exam answers) come from understanding that risk is about both likelihood and severity.  When you start thinking this way, everything else gets easier: prioritizing, choosing actions, and explaining your reasoning with confidence.