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	Projekt podłużny ex post facto	Badania podłużne
Dziedzina	Projektowanie badań	Projektowanie badań
Rodzina	Process / pipeline	Process / pipeline
Rok powstania	1964–1986 (Kerlinger 1964 first edition; Campbell & Stanley 1966)	Late 19th–early 20th century; methodologically codified through the 20th century
Twórca	Fred N. Kerlinger (systematized); Donald T. Campbell & Julian C. Stanley (quasi-experimental framework)	No single originator; foundational methodological treatments by Stuart Menard and Judith Singer & John Willett
Typ	Non-experimental quantitative research design	Quantitative (or mixed) observational research design
Źródło pierwotne	Kerlinger, F. N. (1986). Foundations of Behavioral Research (3rd ed.). Holt, Rinehart and Winston. ISBN: 978-0030417498	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922841
Inne nazwy	longitudinal causal-comparative design, longitudinal after-the-fact design, longitudinal retrospective design, LEPF design	longitudinal study, longitudinal design, prospective longitudinal study, repeated-measures observational study
Pokrewne	5	4
Podsumowanie	A longitudinal ex post facto design combines the time-depth of longitudinal research with the retrospective logic of ex post facto inquiry. Participants are grouped by a naturally occurring characteristic or past event — not randomly assigned — and then observed or measured at multiple points over time. The goal is to trace how pre-existing differences between groups unfold or predict outcomes across an extended period, without the researcher ever manipulating the independent variable.	Longitudinal research is an observational design in which the same participants, groups, or units are measured repeatedly over an extended period. Rather than capturing a single snapshot, it tracks change, stability, and temporal sequencing of variables — making it the primary non-experimental strategy for studying development, growth, decline, and the unfolding of causal processes across time.