Where the light is
2015/11/08 § Leave a comment
During my weekly reading assignment for avoiding pitfalls while conducting research, I came across this wonderful illustration for mistaking a convenience sample for a representative one.
[…] a cop walking a beat at night comes across a man on his knees under a street lamp. The cop asks the man what he is doing. The man replies that he is looking for his car keys. The cop asks where the man lost his keys. The man says, “I don’t know.” The perplexed cop then asks, “Why are you looking here?” only to be told by the man “Because the light is better under the street lamp.”
This illustration perfectly conveys the issue: The man isn’t looking for his car keys under the street lamp because that is where his keys were lost. Rather, he is looking for his keys there because the easiest place to look is where the light is.