CLIO Learning Modules
Study DesignSelectionSample SizeData Collection and AnalysisHuman Subjects

'Me too studies'
Target Population
Attributable Risk
Relative Risk
Data Sources
Study Time
Case Control
Nested Case-Control
Prospective Cohort
Retrospective Cohort
Randomized Clinical Trial
Data Sources

Epidemiologists need to identify the source(s) from which to obtain their study-related information when designing a study. Examples of data sources and their applications are summarized in the following table:

Data Examples of Sources Application(s)

Death certificate, hospital record, school absenteeism, etc.

Surveillance, for examples:
  • Morbidity and Mortality Weekly Report (MMWR)
  • Cancer Surveillance, Epidemiology, and End Results (SEER)

Estimate the prevalence of disease
Ascertain disease and vital status of study population
Estimate frequency of certain cause of death in a population

Estimate the background prevalence of disease
Ascertain cancer occurrence in a study population (SEER data)

Disease-/ exposure-related Survey, for examples,
  • National Health and Nutrition Examination Survey
  • National Hospital Discharge Survey
Provide estimate of health/nutritional status of a population

Personal or Proxy Interview (Questionnaire)


Census Data

Provide past/current life style, dietary habit, exposure to environmental hazard, etc.

Offer evidence of certain environmental exposure or genetic alteration/polymorphism

Give demographic/social-economic information of a population


White et al (Am J Epidemiol. 2004 Jan 1;159(1):83-93) designed a prospective cohort study to examine the association between vitamin supplement use and cancer risk. To obtain data on supplement use, the authors administered a detailed dietary and supplement questionnaire to each subject at the baseline of the study. Because the study population came from regions covered by the Washington State SEER program cancer registry, the authors planned to monitor the cancer occurrence of the study population by linking the individuals to SEER registry annually by means of social security number during the course of the follow-up.

Further reading

Morbidity and Mortality Weekly Report

Cancer Surveillance, Epidemiology, and End Results

U.S. Census Bureau

June 4, 2004 v0.20
Copyright © 2004 Stanford School of Medicine