## Wednesday, April 23, 2008

### Risk Calculations: On the Mark or Missing by a Mile?

Ever since it was mathematically proven that air travel is actually much safer than driving, risk calculations has become a perennial topic of discussion by anyone too worried to be worried. Are we being scared unnecessarily?

By: Vanessa Uy

There’s this very funny anecdote that I heard quite recently about how much air travel is safer compared to your typical “little girls bike”. You also probably heard it before. The punch line goes: “At least when my little girl falls from her bike, its not a 30,000 foot drop. This could very well serve as a rationale for the toy manufacturer Mattel to start competing with the jumbo jet manufacturer Boeing once the scandal over the high lead content of Mattel’s PROC-manufactured toy products eventually dies down.

Basing from such tales of perception and of opinion from the general public with regards to the risks that they face everyday, its no wonder that people who do risk assessment for a living harbor a pre-conceived notion. A notion that the general public is largely irrational when it comes to risk assessment, but there’s a kernel of truth regarding this matter.

Calculations used for risk assessment are based on averages, so they have limited value to the individual. Air travel, for instance, may be safe in terms of deaths per passenger mile. But that says little about the specific flight you are about to board. The very one that will subject you and your fellow passengers to a number of takeoffs and landings in bad weather, not to mention the flight crews’ forays into alcohol addled hedonism that previous night.

To define a certain risk implies that the risk assessor resorts to foretelling, but the accuracy of the math’s predictive power can be misleading. This is so because risk assessors’ calculations – by and large – always use historical data while adhering to the dubious assumption that the future will behave like the past. It seems like risk and uncertainty always goes hand in hand, even under mathematical scrutiny.

On the other end of the risk spectrum, examine for a moment the unthinkable scenario when almost all life on Earth – including humans - being wiped out by a catastrophic comet, meteorite or asteroid impact. Due to Hollywood cashing in the legitimate concerns of astronomers warning us of this “Doomsday Scenario”, the general public has been fascinated on what might happen as we prepare, during, and after a catastrophic asteroid or comet impact during the last ten years or so.

One asteroid that got famous after receiving it’s “15 Minutes of Fame” in the mainstream media spotlight is 99942 Apophis. This 320 meter wide asteroid was first discovered in 2004 and was supposedly calculated to hit our planet on April 13, 2029. Though by no means dead certain, estimates for the asteroid 99942 Apophis hitting us ranges from a “scary” 1 in 27 to NASA’s “somewhat reassuring” official estimate of 1 in 45,000.

As of late, NASA’s official estimate has recently recalculated by an “astronomically curious” high school student using off the shelf computer software. Using such modest resources, the student’s findings that the asteroid 99942 Apophis now has a probability of 1 in 459 in hitting our planet. The student’s findings were later proven by NASA to be correct. But for those who based their calculations via current geological evidence that catastrophic impacts that wiped out the dinosaurs 65 million years occur regularly at 13 million- year intervals. Therefore the chances of our planet being hit catastrophically by a comet or asteroid in a span of one year comes to about 1 in 20,000. Even though I’m worried, I do keep my worries to an absolute-minimum. Anymore than that is an unacceptable risk to my overall wellbeing.