Even though you might not think about it a lot, you often make decisions
in your life based on experiences that they have had or on things that
they have heard about. In such cases you are basing your decisions on
anecdotal evidence.
Let's say a friend of yours claims that a particular brand of inexpensive
shower cleaner is really good. Your friend explains that he simply sprayed
it on the tiles, left it for 10 minutes, and when he came back the tiles
were spotless - without him having scrubbed or done anything else!
This anecdotal evidence is enough of a recommendation for you. You buy
some and use it, thus testing the evidence for yourself.
Another example of anecdotal evidence occurs when we decide not to
go to a particular area because we have heard that an isolated event
such as an horrific crime has occurred there. However, there is an overwhelming
body of evidence that we have a much greater chance of being seriously
injured driving a car locally, and yet we do not hesitate to get in
a car and drive somewhere.
SCENARIO
A friend of yours says he will never wear a seatbelt again.
He explains that an acquaintance of his survived a car accident
because she wasn't wearing a seat belt. The acquaintance
flew through the windscreen, landed on a grassy bank and
suffered minor injuries. Meanwhile the car burst into flames
and was destroyed.
You are not convinced by this story alone that it is a good idea to abandon wearing a seatbelt.
The limitations of anecdotal evidence
The limitations of anecdotal evidence are that often the anecdotes
are curious, peculiar or extraordinary and are not typical or representative.
This causes them to stay in our memory, but it does not make them typical.
This lack of representativeness means that you need
to be careful when making conclusions about a much broader population
from anecdotal evidence.
When to use anecdotal evidence
Despite its limitations, anecdotal evidence is important in some areas
of research, such as case study research, where the emphasis might be
on learning as much as you can about a specific situation and you have
to depend on a person's own experience for information/data. Even
in areas where anecdotal evidence is not considered valid or reliable
for the type of study that you want to conduct, it can strongly suggest
lines of research.
