Would You Run with the Bulls at Pamplona?

Running with the bulls in the Spanish city of Pamplona can lead to serious injury, even death. How risky is it? According to the website FiveThirtyEight, there was a 0.3% chance of being injured in 2014. In a highly unscientific survey I sent out recently, about half of the respondents chose this figure. A little over one-third of the respondents said they would participate in the event if the probability was this low.

But do people who run with the bulls correctly calculate the risk? After all, FiveThirtyEight called the festival "one of the most jarring examples of how imperfect a process natural selection is ... Literally the only point of going is to survive extreme risk (and to slap a bull on the butt, apparently)."

Admittedly, 0.3% seems pretty unlikely. But a percentage is hard to accurately conceptualize and put into perspective. (Thus, for example, the chance of serious injury when running with the bulls is exceedingly higher than the 0.0007% chance of death when skydiving.) Maybe the survey respondents would have looked at things differently if it was stated that 51 people were injured or died in Pamplona in 2014. Such a number is more concrete, thereby possibly raising the level of concern.

Additionally, people often tend to view risk as the chance an event will occur rather than the potential consequences. So while the chance of harm appears quite low (0.3%), the harm itself is significant -- serious injury or death. The adrenaline rush of running with the bulls has to be fairly high to risk leaving this world earlier than you had anticipated.

Such an analysis is helpful when making various other decisions in your life. It's not enough to think about the odds of a negative result occurring, you also should consider the cost incurred if you come out on the wrong side of the bet.