Efficacy, Effectiveness, Pragmatic Trials – Guidance on Terminology and the Advantages of Pragmatic Trials

Clinical research in complementary medicine focuses on a variety of different questions. For example, there are studies that determine the efficacy of a treatment compared to placebo in an experimental setting, whereas others evaluate the effectiveness of an additional treatment in a real-world setting. There is an ongoing discussion about the advantages and limitations of efficacy and effectiveness studies. The need for comparative effectiveness research (CER) is emphasised by the U.S. administration’s decision to spend more than 1 billion USD for this research over the next 2 years with the aim to obtain information that helps clinicians and patients choose those options that best fit the individual patient’s needs and preferences [1]. Although the methods of CER are not entirely new, the federal initiative supports research that is either more comprehensive – i.e., encompassing many more treatments and conditions, as well as more complete outcome measures – ore more relevant to real-world clinical decisions than traditional clinical research [2]. Such comparisons allow going beyond those between medication A and medication B or device A and device B. It is relevant to compare medications or devices with behavioural interventions, either alone or in conjunction with other approaches [3]. The difference between the term efficacy and the term effectiveness is not well known and there seems to be a grey area in the understanding of efficacy and effectiveness studies. This confusion can be seen in previous literature where for example both terms are used synonymously within one and the same study [4]. Therefore, I would like to explain both terms and, additionally, to outline the value of pragmatic trials for complementary and alternative medicine (CAM) using an example from acupuncture research.