Related Web Sites
A broad FAQ on polling and its reliability.
Why Do Campaign Polls Zigzag So Much?
The author describes how polling methods caused fluctuations in
data reported during the Clinton/Dole presidential race.
Ethical Guidlines for Statistical Practice
This document assists students in learning to perform statistical work responsibly.
Anything Go Wrong?
It is rare for any poll to actually ask questions of
every person in a particular group. Usually only a few
members of the group are questioned as a sample of the
Examples of Errors
in the Making
Many factors can keep a poll from being a perfect
indicator of how all of the people in the population
think, feel, or behave. Here are just a few of the ways a
poll can end up being a lot less than 100% accurate:
- Most polls are conducted by telephone. If we use
the phone book to select 500 names at random to
call, we will never question people with unlisted
phone numbers or people who do not have a phone.
- Research indicates that most phones are answered
by women or older people. If you interview only
the people who answer, will you have a biased
- In the United States, about 50% of registered
voters do not vote. A poll of 500 registered
voters might not include anyone who will actually
showup and cast a vote. How might this matter if
a poll reported that of 500 registered voters,
70% said that if the election were held today
they would vote for Fletcher?
- Almost any question will bias the answer to some
degree. For example, the pollsters in our story
might ask, Do you support Higgins or Fletcher? Or
they could ask, Do you support Fletcher or
Higgins? Research indicates that the order in
which the names are listed in the question will
make a difference in the answer a person gives.
- Now that most Americans work outside the home,
there is a very small window of time when
pollsters can reach people by phone. The person
who answers may be tired after a day's work, not
to mention frustrated by a large number of
unsolicited telephone calls. Should we count on
what those people say?
In Daily Life