From Michael Carbone’s listserv
It’s a mistake in reasoning or decision-making that is caused by sticking to our own pre-conceived ideas based upon personal preferences or feelings.
But now comes an article by Brian Costa in the May 13, 2017 issue of the Wall Street Journal under the headline “Why Golfers Overestimate Their Ability.” In it he writes that “New data suggests that most players think they will hit the ball farther than they do…It reveals a persistent-and tough to overcome-cognitive bias that causes most players to regularly choose the wrong club…. They think that they will hit the ball farther than they actually do because they tend to remember and make decisions based upon their best shots in the past while forgetting about the rest of them.”
Mr. Costa goes on to write about a 1999 study which found that “people tend to hold overly favorable views of their abilities in a wide range of social and intellectual disciplines.” And in support of that conclusion he cites a 1992 study which found that “engineers at two Silicon Valley software firms were asked how they ranked relative to their co-workers. Forty two percent of engineers at one firm and 32% of engineers at the other firm rated themselves in the top 5% of performers.” So here we have professionals who should be very good at math reaching a conclusion that is mathematically impossible to support.
The next time that you are tempted to evaluate a case based solely upon good results in similar cases that you settled, think twice. Or if you are tempted to indulge in probabilities such as “I have a seventy-five percent chance of winning,” think about whether you have any data to support your conclusion. If not, are you engaging in guesswork? Are you pulling a number out of the air? And most importantly, will your client buy it?