IDEAS home Printed from https://ideas.repec.org/a/plo/pone00/0132102.html
   My bibliography  Save this article

Randomization Does Not Help Much, Comparability Does

Author

Listed:
  • Uwe Saint-Mont

Abstract

According to R.A. Fisher, randomization “relieves the experimenter from the anxiety of considering innumerable causes by which the data may be disturbed.” Since, in particular, it is said to control for known and unknown nuisance factors that may considerably challenge the validity of a result, it has become very popular. This contribution challenges the received view. First, looking for quantitative support, we study a number of straightforward, mathematically simple models. They all demonstrate that the optimism surrounding randomization is questionable: In small to medium-sized samples, random allocation of units to treatments typically yields a considerable imbalance between the groups, i.e., confounding due to randomization is the rule rather than the exception. In the second part of this contribution, the reasoning is extended to a number of traditional arguments in favour of randomization. This discussion is rather non-technical, and sometimes touches on the rather fundamental Frequentist/Bayesian debate. However, the result of this analysis turns out to be quite similar: While the contribution of randomization remains doubtful, comparability contributes much to a compelling conclusion. Summing up, classical experimentation based on sound background theory and the systematic construction of exchangeable groups seems to be advisable.

Suggested Citation

  • Uwe Saint-Mont, 2015. "Randomization Does Not Help Much, Comparability Does," PLOS ONE, Public Library of Science, vol. 10(7), pages 1-24, July.
    • Handle: RePEc:plo:pone00:0132102
    DOI: 10.1371/journal.pone.0132102
    as

    Download full text from publisher

    File URL: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0132102
    Download Restriction: no
    File URL: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0132102&type=printable
    Download Restriction: no
    File URL: https://libkey.io/10.1371/journal.pone.0132102?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    References listed on IDEAS

    as
    1. David Draper & James S. Hodges & Colin L. Mallows & Daryl Pregibon, 1993. "Exchangeability and Data Analysis," Journal of the Royal Statistical Society Series A, Royal Statistical Society, vol. 156(1), pages 9-28, January.
    Full references (including those not matched with items on IDEAS)

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Jéssica Cordeiro Rodrigues & Mariana Arias Avila & Patricia Driusso, 2021. "Transcutaneous electrical nerve stimulation for women with primary dysmenorrhea: Study protocol for a randomized controlled clinical trial with economic evaluation," PLOS ONE, Public Library of Science, vol. 16(5), pages 1-11, May.
    2. Aufenanger, Tobias, 2018. "Treatment allocation for linear models," FAU Discussion Papers in Economics 14/2017, Friedrich-Alexander University Erlangen-Nuremberg, Institute for Economics, revised 2018.
    3. John Damiao, 2022. "Cumulative Equivalence: Controlling for Inter-Individual Differences at Baseline Characteristic Testing of RCTs," Global Journal of Health Science, Canadian Center of Science and Education, vol. 14(7), pages 1-32, July.

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Courgeau, Daniel, 2012. "Probability and social science : methodologial relationships between the two approaches ?," MPRA Paper 43102, University Library of Munich, Germany.
    2. Jonathan L. Blitstein & Peter J. Hannan & David M. Murray & William R. Shadish, 2005. "Increasing the Degrees of Freedom in Existing Group Randomized Trials," Evaluation Review, , vol. 29(3), pages 241-267, June.
    3. Brock,W.A. & Durlauf,S.N., 2000. "Growth economics and reality," Working papers 24, Wisconsin Madison - Social Systems.
    4. Steven N. Durlauf, 2002. "On the Empirics of Social Capital," Economic Journal, Royal Economic Society, vol. 112(483), pages 459-479, November.
    5. Luger, Richard, 2006. "Exact permutation tests for non-nested non-linear regression models," Journal of Econometrics, Elsevier, vol. 133(2), pages 513-529, August.
    6. Yuli Liang & Dietrich Rosen & Tatjana Rosen, 2021. "On properties of Toeplitz-type covariance matrices in models with nested random effects," Statistical Papers, Springer, vol. 62(6), pages 2509-2528, December.
    7. Sander Greenland, 2001. "Putting Background Information About Relative Risks into Conjugate Prior Distributions," Biometrics, The International Biometric Society, vol. 57(3), pages 663-670, September.

    More about this item

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:plo:pone00:0132102. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: plosone (email available below). General contact details of provider: https://journals.plos.org/plosone/ .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.