Σύγκριση μεθόδων

	Διαχρονική Έρευνα	Έρευνα με Δείγμα
Πεδίο	Μεθοδολογία Επισκοπήσεων	Μεθοδολογία Επισκοπήσεων
Οικογένεια	Process / pipeline	Process / pipeline
Έτος προέλευσης	1940s (panel survey tradition); longitudinal designs codified mid-20th century	Late 19th century; systematic social-science use from 1940s
Δημιουργός	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)	Francis Galton, Charles Booth, and early social statisticians; formalised by Paul Lazarsfeld in the 1940s
Τύπος	Quantitative / mixed-methods survey design	Quantitative (primarily) or mixed-methods data-collection instrument
Θεμελιώδης πηγή	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292	Dillman, D. A., Smyth, J. D., & Christian, L. M. (2014). Internet, Phone, Mail, and Mixed-Mode Surveys: The Tailored Design Method (4th ed.). Wiley. ISBN: 978-1118456149
Εναλλακτικές ονομασίες	panel survey, repeated-measures survey, longitudinal panel study, wave survey	questionnaire survey, survey research, self-report survey, questionnaire 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 survey is a systematic data-collection method in which a standardised set of questions is posed to a sample of respondents to measure attitudes, behaviours, demographics, or other constructs. Surveys can be administered via paper, telephone, online platforms, or face-to-face. They are among the most widely used instruments in social, behavioural, health, and educational research because they can reach large, geographically dispersed samples at relatively low cost.