Residents sometimes submit research grants to the ASHP Foundation in which they propose comparing the efficacy of two medications when they are actually proposing a comparison of effectiveness.  Efficacy and effectiveness are not interchangeable terms.  Given the emphasis on comparative effectiveness studies in the U.S. healthcare system—from policy decisions to direct patient care—it is imperative that pharmacists have a clear understanding of the differences between efficacy and effectiveness.

Schumock and Pickard clearly defined efficacy as a measure of the capacity of a treatment to produce the desired effect in a controlled environment, such as in a randomized controlled trial.  They defined effectiveness as the actual effect of the treatment in practice.

Hébert and colleagues identified 13 domains under which efficacy and effectiveness studies differ. These include the research question, setting, patient selection, study design, baseline assessment, study intervention, co-interventions, compliance, endpoints, analysis, sample size, data management, and study management.

For more information about these articles, click on the references above; this will take you directly to their corresponding PubMed citations.


 Also see:

• Establishing Timelines
• Evaluating the Existing Evidence
• Developing the Research Question, Part I
• Developing the Research Question, Part II
• Writing Specific Aims
• Hypothesis Statements
• Avoiding Bias
• Data Sources
• Study Design
• Survey Research
• Gaining Institutional Support
• Biostatistics
• Human Subjects Protections, Part I
• Human Subjects Protections, Part II
• Data Collection, Display and Manipulation
• Grant Submissions, Part I
• Grant Submissions, Part II
• Grant Submissions, Part III 
• Research Presentations
• Submitting a Manuscript