Page 267 - Statistics for Dummies

Chapter 16: Polls, Polls, and More Polls
in drawing conclusions about. In most situations, surveying the entire target
population (that is, conducting a full-blown census) is impossible because
researchers would have to spend too much time or money to do so. Usually,
the best you can do is to select a sample of individuals from the target popu-
lation, survey those individuals, then draw conclusions about the target
population based on the data from that sample.
Sounds easy, right? Wrong. Many potential problems arise after you realize 251
that you can’t survey everyone in the entire target population. Then, after a
sample is selected, many researchers aren’t sure what to do to get the data
they need. Unfortunately, many surveys are conducted without taking the
time needed to think through these issues, resulting in errors, misleading
results, and wrong conclusions. In the following sections, I give specifics for
the first five steps in the survey process.
Clarifying the purpose of your survey
This sounds like it should just be common sense, but in reality, many surveys
have been designed and carried out that never met their purpose, or that met
only some of the objectives, but not all of them. Getting lost in the questions
and forgetting what you’re really trying to find out is easy to do. In stating the
purpose of a survey, be as specific as possible. Think about the types of con-
clusions you would want to make if you were to write a report, and let that
help you determine your goals for the survey.
Lots of researchers can’t see the forest for the trees. If a restaurant manager
wants to determine and compare satisfaction rates for her customers, she
needs to think ahead about what kinds of comparisons she wants to make
and what information she wants to be able to report on. Questions that pin-
point when the customers came into the restaurant (date and time), or even
what table they were at, are relevant. And if she wants to compare satisfac-
tion rates for, say, adults versus families, she needs to ask how many people
were in the party and how many were children. But if she simply asks a
couple of questions on satisfaction or throws in every question she can think
of, without considering in advance why she needs the information, she may
end up with more questions than answers.
The more specific you can be about the purpose of the survey, the more easily
you can design questions that meet your objectives, and the better off you’ll
be when you need to write your report.

Defining the target population
Suppose, for example, that you want to conduct a survey to determine the
extent to which people send and receive personal e-mail in the workplace.
You may think that the target population is e-mail users in the workplace.
However, you want to determine the extent to which personal e-mail is used
in the workplace, so you can’t just ask e-mail users, or your results would be
biased against those who don’t use e-mail in the workplace. But should you

3/25/11 8:13 PM
24_9780470911082-ch16.indd 251 3/25/11 8:13 PM
24_9780470911082-ch16.indd 251