Prioritizing comparative effectiveness research: are drug and implementation trials equally worth funding?

Comparative effectiveness research (CER) is the generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat and monitor a clinical condition, or to improve the delivery of care. The purpose of this article is to compare--within the scope of CER--the value of implementation and drug trials. Implementation trials have limitations similar to drug trials in terms of generalizability of results outside the trial setting and ability to identify best practice. However, in contrast to drug trials, implementation trials do not provide value in terms of ruling out harm, as implementation strategies are unlikely to cause harm in the first place. Still, implementation trials may provide good value when there is a high error probability in deciding whether implementation will be cost effective or if costs associated with making an erroneous decision are high. Yet the low risk of implementation programmes to cause harm may also allow for alternative approaches to identify best implementation practice, perhaps outside the scope of rigorous trials and testing. One such approach that requires further investigation is a competitive market for quality of care, where implementation programmes may be introduced without prior evaluation.