Figure 3
From: Novel study designs to investigate the placebo response
![Figure 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1471-2288-11-90/MediaObjects/12874_2010_Article_602_Fig3_HTML.jpg)
The "delayed response test" (DRT) design: The "additive model" by Kirsch (2000) assumes that P1 = P2. Under the further assumptions that M1 = M2 and P2 = P3, the hypothesis of the "additive model" is falsified if (M1+ P1 ≠M2 + P3).