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220905P - CROSS-SECTIONAL STUDY 2: ECOLOGIC DESIGN

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Presented at a Webinar on Research Methodology in Health Sciences at Northern Area Armed Forces Hospital (NAAFH) on 5th September 2022. By Professor Omar Hasan Kasule Sr.   MB ChB (MUK). MPH (Harvard), DrPH (Harvard) Professor of Epidemiology and Bioethics


KEYWORDS

  • Survey report
  • The survey, Field Survey
  • The survey, Health Surveys
  • The survey, Morbidity Survey
  • The 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.
  • The 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.