Vertaile menetelmiä

	Ekologinen tutkimus	Aikasarjojen katkosanalyysi (Interrupted Time Series, ITS)
Tieteenala	Epidemiologia	Kausaalipäättely
Menetelmäperhe	Process / pipeline	Regression model
Syntyvuosi	19th century (Snow 1854); formalised mid-20th century	2002
Kehittäjä	Various; foundational work by John Snow (1854) and systematised in modern form by Brian MacMahon and colleagues	Wagner, Soumerai, Zhang & Ross-Degnan (segmented regression); Bernal, Cummins & Gasparrini (tutorial)
Tyyppi	Observational epidemiological study	Quasi-experimental segmented regression
Alkuperäislähde	Morgenstern, H. (1995). Ecologic studies in epidemiology: concepts, principles, and methods. Annual Review of Public Health, 16(1), 61–81.	Bernal, J. L., Cummins, S., & Gasparrini, A. (2017). Interrupted time series regression for the evaluation of public health interventions: a tutorial. International Journal of Epidemiology, 46(1), 348-355.
Rinnakkaisnimet	aggregate study, correlational study, ecological correlation study, population-level study	ITS analysis, segmented regression of time series, Kesintili Zaman Serisi (ITS) Analizi
Liittyvät	5	5
Tiivistelmä	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.	Interrupted Time Series analysis is a quasi-experimental design that estimates the effect of a single, well-dated intervention by comparing the trajectory of an outcome before and after it occurs. Formalised as segmented regression by Wagner and colleagues (2002) and popularised as a public-health evaluation tutorial by Bernal, Cummins and Gasparrini (2017), it separates the intervention's impact into a change in level and a change in slope.