Fig. 1
From: Contextual effects: how to, and how not to, quantify them
Total treatment effect encompasses the specific effects of treatment, contextual effects, and nonspecific effects. The addition of contextual and non-specific effects is called the placebo response. The treatment vs. placebo/sham comparison controls for contextual and nonspecific effects to isolate the specific treatment effect. The placebo vs. no-treatment comparison controls for nonspecific effects to isolate contextual effects. The treatment vs. no-treatment comparison controls for non-specific effects to isolate contextual and specific treatment effects. Adapted from the study by Cashin et al. [18]