Compara mètodes

	Estudi Epidemiològic Transversal	Estudi ecològic
Camp	Epidemiologia	Epidemiologia
Família	Process / pipeline	Process / pipeline
Any d'origen	1960s (formal codification); widely practiced since mid-20th century	19th century (Snow 1854); formalised mid-20th century
Autor original	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)	Various; foundational work by John Snow (1854) and systematised in modern form by Brian MacMahon and colleagues
Tipus	Observational, descriptive/analytic epidemiological design	Observational epidemiological study
Font seminal	Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods in Observational Epidemiology (2nd ed.). Oxford University Press. ISBN: 978-0195080407	Morgenstern, H. (1995). Ecologic studies in epidemiology: concepts, principles, and methods. Annual Review of Public Health, 16(1), 61–81.
Àlies	prevalence study, cross-sectional survey, transversal study, cross-sectional design	aggregate study, correlational study, ecological correlation study, population-level study
Relacionats	6	5
Resum	A cross-sectional epidemiological study measures the exposure(s) and outcome(s) of interest simultaneously in a defined population at a single point in time (or over a short period). Because there is no follow-up, it is the most efficient observational design for estimating disease prevalence and for generating hypotheses about associations between risk factors and health outcomes.	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.