Understanding the Fundamentals of Epidemiology an evolving text

(normal) distribution in the population. Other assumptions are those made about reality. For
example, what if a person responds to the question on race by circling 3 responses, Black, Hispanic,
and White. There is a study protocol to classify such an individual; however, this protocol may
differ from other similar studies or the U.S. Census, or state birth certificates, etc. This may have an
impact on the expected distribution and /or interpretation.
3.9 Examination of study questions
Data analyses may be approached in an exploratory fashion or in pursuit of answers to
specific questions. Ideally the latter should have been specified in the research proposal or well
before the analysis process has begun. Often new questions (or all questions) are formulated during
the analysis process. In either case, it is highly desirable to articulate specific questions as a guide to
how to proceed in the data analysis.
Besides their relevance to the questions at hand, analyses generally need to reflect the study
design. For example, cross-sectional designs do not provide direct estimates of incidence, matched
designs may warrant matched analyses.
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rev. 9/27/1999, 10/22/1999, 10/28/1999