Σύγκριση μεθόδων

	Διαχρονική Έρευνα	Μελέτη κοόρτης
Πεδίο	Μεθοδολογία Επισκοπήσεων	Επιδημιολογία
Οικογένεια	Process / pipeline	Process / pipeline
Έτος προέλευσης	1940s (panel survey tradition); longitudinal designs codified mid-20th century	Mid-20th century (formal epidemiological design codified ~1950s)
Δημιουργός	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
Τύπος	Quantitative / mixed-methods survey design	Observational longitudinal study design
Θεμελιώδης πηγή	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
Εναλλακτικές ονομασίες	panel survey, repeated-measures survey, longitudinal panel study, wave survey	longitudinal study, follow-up study, panel study, incidence study
Συναφείς	3	6
Σύνοψη	A longitudinal survey collects structured questionnaire data from the same individuals or units at two or more distinct points in time. By tracking the same respondents across waves, researchers can distinguish genuine change from stable individual differences, establish temporal ordering between variables, and model trajectories of attitudes, behaviors, or outcomes in ways that a single cross-sectional snapshot cannot support.	A cohort study assembles a group of individuals who share a common starting point — typically freedom from the outcome of interest — and follows them over time to observe who develops the outcome. By comparing incidence rates between exposed and unexposed subgroups, researchers can estimate relative risk and absolute risk differences. Cohort studies are the gold-standard observational design for measuring disease incidence and establishing temporal relationships between exposure and outcome.