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Presented at CRC course KFMC on January 28, 2020 by Prof Omar Hasan Kasule Sr Professor of Epidemiology and Bioethics, King Fahad Medical City.
Keywords:
• Survey report
• Survey, Field Survey
• Survey, Health Surveys
• Survey, Morbidity Survey
• Survey, Nutrition Survey
ECOLOGIC DESIGN:
• Ecological studies, exploratory or analytic, study aggregate and not individual information.
• Groups commonly used are schools, factories, and countries.
• Exposure is measured as an overall group index.
• Outcome is measured as rates, proportions, and means.
• The correlation and regression coefficients are used as effect measures.
ADVANTAGES OF ECOLOGIC/CORRELATION STUDIES
• low cost,
• convenience,
• easy analysis,
• easy interpretation.
DISADVANTAGES OF ECOLOGIC STUDIES
• They generate but cannot test hypotheses.
• They cannot be used in definitive etiological research.
• They suffer from ecological fallacy (relation at the aggregate is not true at the individual level). They lack data to control for confounding.
• Data is often inaccurate or incomplete.
• Collinearity is a common problem.