Skip to main content
Log in

Are RCTs the Gold Standard?

  • Article
  • Published:
BioSocieties Aims and scope Submit manuscript

Abstract

The claims of randomized controlled trials (RCTs) to be the gold standard rest on the fact that the ideal RCT is a deductive method: if the assumptions of the test are met, a positive result implies the appropriate causal conclusion. This is a feature that RCTs share with a variety of other methods, which thus have equal claim to being a gold standard. This article describes some of these other deductive methods and also some useful non-deductive methods, including the hypothetico-deductive method. It argues that with all deductive methods, the benefit that the conclusions follow deductively in the ideal case comes with a great cost: narrowness of scope. This is an instance of the familiar trade-off between internal and external validity. RCTs have high internal validity but the formal methodology puts severe constraints on the assumptions a target population must meet to justify exporting a conclusion from the test population to the target. The article reviews one such set of assumptions to show the kind of knowledge required. The overall conclusion is that to draw causal inferences about a target population, which method is best depends case-by-case on what background knowledge we have or can come to obtain. There is no gold standard.

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

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Notes

  1. 1 This must include ‘spontaneous generation’. More formally, Ki holds fixed one variable on each pathway that does not go through T, as judged by the causal structure CS.

  2. 2 In the ‘long run’, of course, since all results are probabilistic.

  3. 3 Or as near enough as matters for our purposes. I shall here ignore these niceties and how to treat them in order to focus on the main point.

References

  • Cartwright N. (1989). Nature's capacities and their measurement. Oxford: Clarendon Press.

    Google Scholar 

  • Cartwright N. (forthcoming). Hunting causes and using them. Cambridge: Cambridge University Press.

  • Granger C. (1969). Investigating causal relations by econometric models and cross-special methods. Econometrica, 37, 424–438.

    Article  Google Scholar 

  • Heckman J. (2001). Econometrics, counterfactuals and causal models. Keynote Address, International Statistical Institute, Seoul, Korea.

  • Holland P.W., & Rubin D.B. (1988). Causal inference in retrospective studies. Evaluation Review, 12, 203–231.

    Article  Google Scholar 

  • Suppes P. (1970). Probabilistic theory of causality. Atlantic Highlands, NJ: Humanities Press.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Cartwright, N. Are RCTs the Gold Standard?. BioSocieties 2, 11–20 (2007). https://doi.org/10.1017/S1745855207005029

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1017/S1745855207005029

Keywords

Navigation