The 85th Percentile

Philip Morgan

Recently a woman in a wheelchair got run over by an older man driving a car here in Sebastopol.This happened at what is considered a pretty dangerous intersection for pedestrians. For several not-that-interesting reasons, it's a place where it just feels risky to cross the street.One of those reasons is the speed limit of 40 miles per hour at that intersection.Like many locals, I'm all for lowering the speed limit at that intersection, but I recently learned that it would be illegal to do so because of something called "the 85th percentile".From one of the local newspapers:------As Sebastopol Police Captain James Conner explained, any speed lower than the current rate of 40 miles per hour would not be enforceable by law. Speeds are set according to California state law, which requires municipalities to set the speed limit at the speed that 85 percent of people drive. Known as the 85th percentile, the measure is established by an engineering traffic study during which a certified engineer uses radar to record the speed of 100 drivers. The speed of 85 percent of those drivers is considered by state law to be “common sense” for safe drivers and therefore a reasonable speed.------If you were to apply this 85th percentile idea to your business positioning, and if furthermore your positioning involves a focus on a technology, then you'd be focused on very mature technologies; stuff that is somewhere between late majority and laggard adoption status:ImageA couple of problems here, in no particular order:

  • When a technology or platform is mature (a few examples: PHP, Windows, mobile), buying behavior is very pragmatic and risk-averse. At the same time, the supply of tech/platform expertise is high and includes options at all price points. Guess what that does to prices if your only value is tech expertise alone?
  • At tech/platform maturity, best practices around the basics of using the technology are pretty well-established. Guess what this does to the value of your advice?

Does this mean you should focus on less mature technologies?It depends. You can get some answers that are specific to you and your situation in Know a self-employed software developer who might benefit from specialization? Send 'em this free gift! Details here --> /referrals/