Interrupted time series
Research Methods
Definition. Interrupted time series is a quasi-experimental design that evaluates an intervention by comparing the level and trend of an outcome measured repeatedly before and after the intervention.
Explanation
The usual analysis is segmented regression, which estimates the change in level immediately after the intervention and the change in slope afterwards, while accounting for the pre-existing trend (Wagner et al., 2002).
Bernal, Cummins and Gasparrini (2017) describe the design as one of the strongest alternatives to randomised trials for evaluating policies and service changes. Threats include other events occurring at the same time, seasonality and autocorrelation, and too few data points before or after the change.
Related concepts
Causal inference Quality improvement Statistical process control
Read on The Health Topics
- Interrupted Time Series Design in Healthcare: Methodology and Reporting
- DAGs and Target Trial Emulation for Oncology Management Research: Eight Causal Chains
- Evaluating Knowledge Translation Interventions: A Primer
- Thematic Review of the Health Policy Literature: A Report on the Top 50 Most Cited Articles in Web of Science
- Evidence-Based Critique in Higher Education Quality Assurance: A Four-Type Policy Gap Analysis of the YÖKAK Institutional Self-Evaluation Rubric (v3.2.1)
- Realist Evaluation and QCA of Complex Interventions in Oncology Management: MDT, Telehealth/ePRO and QA/QI
References
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.
Wagner, A. K., Soumerai, S. B., Zhang, F., & Ross-Degnan, D. (2002). Segmented regression analysis of interrupted time series studies in medication use research. Journal of Clinical Pharmacy and Therapeutics, 27(4), 299–309.
Cite this entry: Kurutkan, M. N. (2026). Interrupted time series. In The Health Topics glossary. https://healthtopic.org/glossary/interrupted-time-series/
Articles that discuss this concept
9 articles on The Health Topics use this concept. The list updates as new articles are published.
- Interrupted Time Series Design in Healthcare: Methodology and Reporting 4
- Thematic Review of the Health Policy Literature: A Report on the Top 50 Most Cited Articles in Web of Science 3
- DAGs and Target Trial Emulation for Oncology Management Research: Eight Causal Chains 3
- Evaluating Knowledge Translation Interventions: A Primer 2
- When theatres wait: a new Lean 4.0 study and the research it invites 1
- Managing Waiting in Health Services: Strategies, Techniques and Measurement 1
- Causal Chain Analysis in Oncology Management Research: Dependent, Independent, Mediating, Moderating and Control Variables 1
- Realist Evaluation and QCA of Complex Interventions in Oncology Management: MDT, Telehealth/ePRO and QA/QI 1
- Evidence-Based Critique in Higher Education Quality Assurance: A Four-Type Policy Gap Analysis of the YÖKAK Institutional Self-Evaluation Rubric (v3.2.1) 1