## Saturday, January 19, 2013

### Do The Numbers

In view of my recent crash on the ski slopes and resultant injury, I am interested in the frequency of injuries by skiers.   A bit of research shows that one could expect 2.0 to 2.5 injuries per 1000 skier days.  I am not sure how that translates to the vulnerability of individual skiers since this is an aggregate set of data involving thousands if not millions of different kinds of skiers.
So I am trying to assess my probability of injury again, if I were to resume skiing.  Perhaps there are two parts to this.  One is the probability of having a fall and the other is the probability of something beyond a sprain or minor bruise.     For the past 14 years I have logged my ski days and the conditions and any unusual incidents.   Although I skied in the  1960's, 1970's and through 1982, I did not record my ski days.   Therefore, I can only document about 1500 skier days before I sustained my injury.   Thus my injury rate is about 0.67 per 1000 skier days.  Thus I was able to beat the odds for a considerable time.
The injury frequency data does not break out for different age groups so I have no idea if the injury rate is higher for geezer skiers.   Probably it is higher since we do get a bit more fragile as we age.
After one does the numbers for skiers, you might ask what about other activities?   I suspect that if one uses the same number of hours of the activity that biking, tennis, basketball and soccer would show high rates of injury.   Because one is not likely to spend several hours at these activities on a daily basis there is compensatory reduction in the amount of injuries.
Whatever the statistics show, the bottom line is what happens to one personally that counts.   Life in all forms has its risks.  The question is what are foolhardy risks given the circumstances and what a reasonable calculated risks.   I guess geezerhood should drive us toward being more risk adverse.   To all the geezer skiers out there, best wishes for safe skiing and making good decisions about calculated risks.

 Snow sport On piste injury rate(IPTSD) On piste injury rate(MDBI) 1. Telemark skiing 1.13 889 2. Skiboarding 1.99 501 3. Alpine skiing 2.38 419 4. Snowboarding 5.31 188 All sports combined 2.59 386

IPTSD = Injuries per 1000 skier days - the average number of people who will be injured for every 1000 people skiing, snowboarding or skiboarding at a ski area on any given day

MDBI = Mean days between injury = the number of days you would have to participate in a particular snow sport before being injured - so the higher the number, the lower the risk. If you're confused, both concepts are fully explained here