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The
methods of the sample survey have been well developed over the
last 40 years. A sampling frame is established enumerating persons
or sampling units in a defined population of interest. A probability
sample is selected from the sampling frame using methods that
may be relatively simple (e.g. a simple random sample) or complex
(e.g. a multi-stage cluster sample). The methods of probability
sampling are fully treated in a number of texts (Kish,
1965; Cochran,
1977).
Information
to determine the presence or absence of TMD pain and concerning
possible risk factors is collected by interview usually conducted
either in-person or via telephone. The interview typically follows
a standardized questionnaire administered by a trained interviewer
with response categories pre-coded. In some instances, a two-phase
survey design can be employed to permit clinical examination and
diagnostic evaluation of a sub-sample of persons included in the
sample survey (e.g. Dworkin
et al., 1990a; List
et al., 1999). Selection of the sub-sample may be based on
responses to the initial survey interview.
Example
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excellent example of the kinds of information that can
be developed through morbidity surveys of pain syndromes
is provided by a national survey of the prevalence of
migraine conducted by Stewart
et al. (1992). They collected data on migraine symptoms
from a national sample of over 20,000 persons aged 12
to 80 years. Migraine status was determined using a
clinically validated algorithm based on diagnostic criteria
of the International Headache Society. They found the
17.6% of females and 5.7% of males had experienced a
migraine headache in the prior year, and that migraine
prevalence was higher among low income groups, and peaked
in the 35-44 year age group. |
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