A key risk indicator is something that helps people understand how risky something might be. It helps us decide if we should do something or not and how much care we should take when doing it. For example, let's say you want to buy a car. One key risk indicator you could use would be how many times the car has been in an accident. If the car has been in a lot of accidents, it might be a lot riskier to buy than if it had only been in one accident. That information can help you decide how much you're willing to pay for the car, and how much care you should take when driving it.