Health Services Research (HSR) Methods
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Non-randomized Trial with Historical Controls

A study in which investigators compare outcomes among a group of patients who are receiving a new treatment with outcomes among patients who received standard treatment in a previous period. In these studies, patients receiving new treatment compose the experimental group and patients who received standard treatment are historical controls.

Bias may be a concern in this approach when subjects receiving new treatment are not comparable to subjects who received traditional treatment.


Further Reading
Berger, M. et al. 2003. Health Care, Cost, Quality, and Outcomes: ISPOR Book of Terms, Lawrenceville, NJ: International Society for Pharmacoeconomics and Outcomes Research.