השוואת שיטות

	מערך מחקר בדיעבד	מחקר אורך
תחום	תכנון מחקר	תכנון מחקר
משפחה	Process / pipeline	Process / pipeline
שנת המקור	1960s (systematic codification); concept used in social science from early 20th century	Late 19th–early 20th century; methodologically codified through the 20th century
הוגה השיטה	Formalized by Fred N. Kerlinger; foundational treatment by Donald T. Campbell and Julian C. Stanley	No single originator; foundational methodological treatments by Stuart Menard and Judith Singer & John Willett
סוג	Non-experimental quantitative research design	Quantitative (or mixed) observational research design
מקור מכונן	Kerlinger, F. N. (1964). Foundations of Behavioral Research. Holt, Rinehart and Winston.	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922841
כינויים	after-the-fact research, retrospective non-experimental design, causal-comparative design, EPF design	longitudinal study, longitudinal design, prospective longitudinal study, repeated-measures observational study
קשורות	3	4
תקציר	Ex post facto design is a non-experimental quantitative research approach in which the researcher investigates a phenomenon after it has already occurred, examining pre-existing differences between groups to explore potential causal or associative relationships. Because the independent variable cannot be manipulated — it happened in the past — the design relies on careful group selection, retrospective data collection, and statistical controls to approximate causal inference without experimental intervention.	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.