Standardized or simple effect size: What should be reported?

It is regarded as best practice for psychologists to report effect size when disseminating quantitative research findings. Reporting of effect size in the psychological literature is patchy—though this may be changing—and when reported it is far from clear that appropriate effect size statistics are...

Full description

Bibliographic Details
Published in:British Journal of Psychology Vol. 100; no. 3; pp. 603 - 618
Main Author: Baguley, Thom
Format: Article
Published: Wiley-Blackwell August 2009
Subjects:
Online Access:View this record in EBSCOhost
fields @attributes:
  recordID: 1
pdfLink:
plink: https://search.ebscohost.com/login.aspx?direct=true&db=ssf&AN=510879553&site=ehost-live
header:
  @attributes:
    shortDbName: ssf
    uiTerm: 510879553
    longDbName: Social Sciences Full Text (H.W. Wilson)
    uiTag: AN
  controlInfo:
    bkinfo:
    jinfo:
      jid:
        00071269
        BJP
      jtl: British Journal of Psychology
      issn: 00071269
      maglogo: N
    pubinfo:
      dt: August 2009
      vid: 100
      iid: 3
      pid: 480
      pub: Wiley-Blackwell
    artinfo:
      ui:
        510879553
        10.1348/000712608X377117
      ppf: 603
      ppct: 15
      formats:
        fmt:
          – @attributes:
              type: T
          – @attributes:
              type: P
              size: 1.2MB
      tig:
        atl: Standardized or simple effect size: What should be reported?
      aug:
        au: Baguley, Thom
      su:
        Psychological research
        Effect sizes (Statistics)
        Psychological techniques
        Psychology -- Statistical methods
      sug:
        subj:
          Psychological research
          Effect sizes (Statistics)
          Psychological techniques
          Psychology -- Statistical methods
      ab: It is regarded as best practice for psychologists to report effect size when disseminating quantitative research findings. Reporting of effect size in the psychological literature is patchy—though this may be changing—and when reported it is far from clear that appropriate effect size statistics are employed. This paper considers the practice of reporting point estimates of standardized effect size and explores factors such as reliability, range restriction and differences in design that distort standardized effect size unless suitable corrections are employed. For most purposes simple (unstandardized) effect size is more robust and versatile than standardized effect size. Guidelines for deciding what effect size metric to use and how to report it are outlined. Foremost among these are: (i) a preference for simple effect size over standardized effect size, and (ii) the use of confidence intervals to indicate a plausible range of values the effect might take. Deciding on the appropriate effect size statistic to report always requires careful thought and should be influenced by the goals of the researcher, the context of the research and the potential needs of readers. Reprinted by permission of the publisher.
      pubtype: Academic Journal
      doctype: Article
      src: R
    language: English
    refInfo:
    copyright:
      @attributes:
        flag: N
    holdings:
      @attributes:
        islocal: N