Presented at a Pediatric Research Course held at King Fahad Medical City, Riyadh via Online on Tuesday, 30 March 2021 (13:00 – 15:00 HRS). 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.
ADVANTAGES OF ECOLOGIC/CORRELATION STUDIES
- The correlation and regression coefficients are used as effect measures.
- 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.