Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

‘Placebos’ and the logic of placebo comparison


Robin Nunn has argued that we should stop using the terms ‘placebo’ and ‘placebo effect’. I argue in support of Nunn’s position by considering the logic of why we perform placebo comparisons. Like all comparisons, placebo comparison is just a case of comparing one thing with another, but it is a mistake, I argue, to think of placebo comparison as a case where something is compared to ‘a placebo’. Rather, placebo comparison should be understood as a situation which sets-up the treatment and control groups in a particular way; not as a case involving objects or procedures called ‘placebos’ employed in order to control for ‘placebo effects’.

This is a preview of subscription content, log in to check access.


  1. 1.

    The concern in this paper is with placebo comparison, and so the argument is about the use of the term ‘placebo’ in a research context. Clearly however, the term has uses in clinical contexts that may be valid for independent reasons. I would expect the argument made here to apply to the clinical context; since the general idea is simply that the term obscures what can be better explained in more precise terms. However I will not argue explicitly for this here.

  2. 2.

    Although note that such a principle does not imply that we cannot know that a treatment is efficacious unless a placebo comparison has been performed. It simply equates efficacious treatments with placebo outperforming treatments. If we know a treatment is efficacious, that justifies the belief that it would outperform placebo, were such a comparison to be performed.

  3. 3.

    Or more precisely, a pill with no therapeutically relevant contents (cf. Golomb 1995; Golomb et al. 2010).

  4. 4.

    Actually I’m just assuming they were sugar pills. We are told in the Branthwaite & Cooper’s methods section (1981, p. 1576) that the pills not containing aspirin were the same size, shape, weight and colour, and that they were not designed to taste the same as aspirin tablets. The content of these pills is not disclosed.

  5. 5.

    Note aside that only some aspects of a treatment can be controlled for by randomisation (if that is, any can. See: Worrall 2007, 2010). In practice randomisation and the subsequent adjustment of baseline imbalances helps to minimise, for example, the influence of patients’ differing expectations. However even in the ideal case randomisation would not help at all to solve the problem of treatment groups that were under the supervision of ‘nasty doctor’ on the one hand and ‘nice doctor’ on the other. The attitude and behaviour of the treating physician is something that we must seek to homogenise between groups through other means.

  6. 6.

    Use of the term ‘placebo’ could also be important in a different way, if that usage created therapeutically relevant expectations in a patient. For example in a clinical context, through being told one is receiving ‘a placebo’; or in a research context, through being enrolled in a trial and told that one may be randomised to a placebo group. See for example: Kaptchuk et al. (2010) and Enck et al. (2011).


  1. Adler HM, Hammett V (1973) The doctor-patient relationship revisited: an analysis of the placebo effect. Ann Intern Med 78(4):595–598

  2. Amanzio M, Pollo A, Maggi G, Benedetti F (2001) Response variability to analgesics: a role for non-specific activation of endogenous opioids. Pain 90(3):205–215

  3. Blackwell B, Bloomfield S, Buncher C (1972) Demonstration to medical students of placebo responses and non-drug factors. Lancet 299(7763):1279–1282

  4. Blasi ZD, Harkness E, Ernst E, Georgiou A, Kleijnen J (2001) Influence of context effects on health outcomes: a systematic review. Lancet 357(9258):757–762

  5. Branthwaite A, Cooper P (1981) Analgesic effects of branding in treatment of headaches. Br Med J 282(6276):1576–1578

  6. Cartwright N (2007) Are RCTs the gold standard? BioSocieties 2(1):11–20

  7. Cobb LA, Thomas GI, Dillard DH, Merendino KA, Bruce RA (1959) An evaluation of internal-mammary-artery ligation by a double-blind technic. N Engl J Med 260(22):1115–1118

  8. de Craen AJM, Moerman DE, Heisterkamp SH, Tytgat GNJ, Tijssen JGP, Kleijnen J (1999) Placebo effect in the treatment of duodenal ulcer. Br J Clin Pharmacol 48(6):853–860

  9. Dimond EG, Kittle CF, Crockett JE (1960) Comparison of internal mammary artery ligation and sham operation for angina pectoris. Am J Cardiol 5:483–486

  10. Enck P, Klosterhalfen S, Weimer K, Horing B, Zipfel S (2011) The placebo response in clinical trials: more questions than answers. Philos Trans Royal Soc B 366(1572):1889–1895

  11. Ernst E, Resch K-L (1995) Concept of true and perceived placebo effects. Br Med J 311:551–553

  12. Golomb B (1995) Paradox of placebo effect. Nature 375:530

  13. Golomb B, Erickson L, Koperski S, Sack D, Enkin M, Howick J (2010) What’s in placebos: who knows? Analysis of randomized, controlled trials. Ann Intern Med 153(8):532

  14. Gøtzsche PC (1994) Is there logic in the placebo? Lancet 344(8927):925–926

  15. Gøtzsche PC (1995) Placebo effects. Concept of placebo should be discarded. Br Med J 311(7020):1640

  16. Grünbaum A (1981) The placebo concept. Behav Res Ther 19(2):157

  17. Grünbaum A (1991) The Placebo Concept in Medicine and Psychiatry. In: Cicchetti D, Grove WM (eds) Thinking Clearly about Psychology, Volume I: Matter of Public Interest. University of Minnesota Press, Oxford

  18. Hahn RA, Kleinman A (1983) Belief as pathogen, belief as medicine: “Voodoo death” and the” placebo phenomenon” in anthropological perspective. Med Anthropol Q 14(4):3–19

  19. Hill A (1951) The clinical trial. Br Med Bull 7(4):278–282

  20. Howick J (2009) Questioning the methodologic superiority of ‘placebo’over ‘active’controlled trials. Am J Bioethics 9(9):34–48

  21. Hrobjartsson A, Gøtzsche PC (2001) Is the placebo powerless? An analysis of clinical trials comparing placebo with no treatment. N Engl J Med 344(21):1594–1602

  22. Hrobjartsson A, Gøtzsche PC (2004) Is the placebo powerless? Update of a systematic review with 52 new randomized trials comparing placebo with no treatment. J Intern Med 256(2):91–100

  23. Kaptchuk TJ (2002) The placebo effect in alternative medicine: can the performance of a healing ritual have clinical significance? Ann Intern Med 136(11):817–825

  24. Kaptchuk TJ, Friedlander E, Kelley JM, Sanchez MN, Kokkotou E et al (2010) Placebos without deception: a randomized controlled trial in irritable bowel syndrome. PLoS ONE 5(12):e15591

  25. Kirmayer LJ (2004) The cultural diversity of healing: meaning, metaphor and mechanism. Br Med Bull 69(1):33–48

  26. Koshi E, Short C (2007) Placebo theory and its implications for research and clinical practice: a review of the recent literature. Pain Pract 7(1):4–20

  27. Miller FG, Kaptchuk TJ (2008) The power of context: reconceptualizing the placebo effect. J R Soc Med 101:222–225

  28. Moerman DE (2000) Cultural variations in the placebo effect: ulcers, anxiety, and blood pressure. Med Anthropol Q (New Series) 14(1):51–72

  29. Moerman DE (2002) Meaning, Medicine, and the ‘Placebo Effect’. Cambridge University Press, Cambridge

  30. Moerman DE, Jonas WB (2002) Deconstructing the placebo effect and finding the meaning response. Ann Intern Med 136(6):471–476

  31. Moerman D, Benoist J, Brody E, Giovannini M, Gracia M, Hall E, Heggenhougen H, Jonas D, Kearney M, Kedenburg D (1979) Anthropology of symbolic healing [and comments and reply]. Curr Anthropol 20(1):59–80

  32. Nunn R (2009a) It’s time to put the placebo out of our misery. Br Med J 338(apr20 2):b1568

  33. Nunn R (2009b) Preparing for a post-placebo paradigm: ethics and choice of control in clinical trials. Am J Bioethics 9(9):51–52

  34. Ong L, De Haes J, Hoos A, Lammes F (1995) Doctor-patient communication: a review of the literature. Soc Sci Med 40(7):903–918

  35. Papakostas YG, Daras MD (2001) Placebos, placebo effect, and the response to the healing situation: the evolution of a concept. Epilepsia 42(12):1614–1625

  36. Price L (1984) Art, science, faith and medicine: the implications of the placebo effect. Sociol Health Illn 6(1):61–73

  37. Price DD, Finniss DG, Benedetti F (2008) A comprehensive review of the placebo effect: recent advances and current thought. Annu Rev Psychol 59:565–590

  38. Rabkin JG, Markowitz JS, Stewart J, McGrath P, Harrison W, Quitkin FM, Klein DF (1986) How blind is blind? Assessment of patient and doctor medication guesses in a placebo-controlled trial of imipramine and phenelzine. Psychiatry Res 19:75–86

  39. Shapiro AK (1964) A historic and heuristic definition of the placebo. Psychiatry 27:52–58

  40. Shapiro AK (1968) Semantics of the placebo. Psychiatr Q 42(4):653–695

  41. Shapiro AK, Shapiro E (1997a) The Placebo: Is It Much Ado About Nothing? In: Harrington A (ed) The Placebo Effect: An Interdisciplinary Exploration. Harvard University Press, London

  42. Shapiro AK, Shapiro E (1997b) The Powerful Placebo. Johns Hopkins University Press, London

  43. Stein HF (1983) On Placebos. Medicine after the Demise of” The Placebo”. Medical Anthropology Quarterly:4–17, To Cure, to Control, to Please

  44. Stewart-Williams S, Podd J (2004) The placebo effect: dissolving the expectancy versus conditioning debate. Psychol Bull 130(2):324–340

  45. Temple R, Ellenberg S (2000) Placebo-controlled trials and active-control trials in the evaluation of new treatments. Part 1: ethical and scientific issues. Ann Intern Med 133(6):455–463

  46. Thompson J, Ritenbaugh C, Nichter M (2009) Reconsidering the placebo response from a broad anthropological perspective. Cult Med Psychiatry 33(1):112–152

  47. Worrall J (2007) Evidence in medicine and evidence-based medicine. Philos Compass 2(6):981–1022

  48. Worrall J (2010) Evidence: philosophy of science meets medicine. J Evaluation Clin Pract 16(2):356–362

Download references


Thanks to those at the 2010 ‘Progress in Medicine’ conference in Bristol who offered comments on a very early version of this paper, and thanks to Robin Nunn for comments on a much more recent version. Thanks also to the helpful comments of the anonymous reviewers.

Author information

Correspondence to Andrew Turner.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Turner, A. ‘Placebos’ and the logic of placebo comparison. Biol Philos 27, 419–432 (2012). https://doi.org/10.1007/s10539-011-9289-8

Download citation


  • Placebo
  • Placebo controlled trial
  • Clinical trials
  • Evidence-based medicine