Jämför metoder

	Policyutvärdering med avbruten tidsserie	Differens-i-differens (DiD)
Ämnesområde	Kausal inferens	Ekonometri
Familj	Regression model	Regression model
Ursprungsår	1975 (intervention analysis); 2000s–2010s (policy evaluation framing)	1994
Upphovsperson	Box & Tiao (1975); popularised for policy by Shadish, Cook & Campbell (2002) and Bernal et al. (2017)	Card & Krueger (canonical 1994 application); Angrist & Pischke (textbook treatment)
Typ	Quasi-experimental causal design	Causal inference / panel regression
Ursprungskälla	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.	Angrist, J. D., & Pischke, J.-S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton University Press. ISBN: 978-0691120355
Alias	ITS for policy evaluation, policy ITS, segmented regression for policy, policy impact ITS	diff-in-diff, DiD, Farkların Farkı (Diff-in-Diff)
Närliggande	4	5
Sammanfattning	Interrupted Time Series (ITS) for policy evaluation uses routinely collected aggregate time-series data to estimate the causal impact of a policy change. A segmented regression model splits the series at a known intervention date, estimating both an immediate level shift and a change in trend attributable to the policy — without requiring a randomised control group.	Difference-in-Differences is a causal-inference method that estimates the effect of an intervention by comparing how a treatment group and a control group change over time. Made famous by Card and Krueger's 1994 minimum-wage study and developed in Angrist and Pischke's Mostly Harmless Econometrics, it isolates the treatment effect as the difference between the two groups' before-after changes.