Skip Navigation Bar

National Information Center on Health Services Research and Health Care Technology (NICHSR)

Page 7 of 36
Surveys rely on statistical inference to derive estimates.

They infer:
  • Relationships and generalizations based on sampling theory
  • Conditions and characteristics based on responses to set questions and
  • Trends over time based on cross-sectional observations--

Surveys :
  • Do not usually follow particular cases,
  • But ask about conditions in the past and
  • Infer trends based on repeated observations of different samples of the population rather than following particular individuals.

Survey inferences assume:
  • That the population "covered" is relevant to the generalizations and conclusions
  • That the sample correctly “represents” the population
  • That the questions asked elicit information about the factors, conditions and constructs inferred and
Changes over time can be observed by looking at different people at different times—rather than following individuals and collecting information at multiple times.
Page 7 of 36