Linganisha mbinu

	Utafiti wa Retrospektivu wa Epidemiolojia wa Sehemu Mtambuka	Utafiti wa Ikolojia
Nyanja	Epidemiolojia	Epidemiolojia
Familia	Process / pipeline	Process / pipeline
Mwaka wa asili	Mid–late 20th century	19th century (Snow 1854); formalised mid-20th century
Mwanzilishi	Epidemiology tradition (formalized in mid-20th century; Rothman, Greenland and others)	Various; foundational work by John Snow (1854) and systematised in modern form by Brian MacMahon and colleagues
Aina	Observational study design	Observational epidemiological study
Chanzo asilia	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641	Morgenstern, H. (1995). Ecologic studies in epidemiology: concepts, principles, and methods. Annual Review of Public Health, 16(1), 61–81.
Majina mbadala	retrospective cross-sectional survey, record-based cross-sectional study, retrospective prevalence study, secondary-data cross-sectional study	aggregate study, correlational study, ecological correlation study, population-level study
Zinazohusiana	5	5
Muhtasari	A retrospective cross-sectional epidemiological study measures the prevalence of exposures and outcomes at a single analytical time point using data that were originally recorded in the past — such as medical records, administrative databases, or disease registries. It combines the snapshot logic of a cross-sectional design with the efficiency of retrospective data access, making it a practical choice when prospective data collection is unfeasible or when large existing datasets are available.	An ecological study is an observational epidemiological design in which the unit of analysis is a group or population — a country, region, city, or time period — rather than an individual. Exposures and outcomes are measured as aggregates (rates, proportions, or means) and then correlated across groups to generate or evaluate hypotheses about population-level associations between risk factors and disease.