When the Numbers Do Not Add Up: The Practical Limits of Stochastologicals for Soft Psychology

Nick J. Broers*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


One particular weakness of psychology that was left implicit by Meehl is the fact that psychological theories tend to be verbal theories, permitting at best ordinal predictions. Such predictions do not enable the high-risk tests that would strengthen our belief in the verisimilitude of theories but instead lead to the practice of null-hypothesis significance testing, a practice Meehl believed to be a major reason for the slow theoretical progress of soft psychology. The rising popularity of meta-analysis has led some to argue that we should move away from significance testing and focus on the size and stability of effects instead. Proponents of this reform assume that a greater emphasis on quantity can help psychology to develop a cumulative body of knowledge. The crucial question in this endeavor is whether the resulting numbers really have theoretical meaning. Psychological science lacks an undisputed, preexisting domain of observations analogous to the observations in the space-time continuum in physics. It is argued that, for this reason, effect sizes do not really exist independently of the adopted research design that led to their manifestation. Consequently, they can have no bearing on the verisimilitude of a theory.

Original languageEnglish
Article number1745691620970557
Pages (from-to)698-706
Number of pages9
JournalPerspectives on Psychological Science
Issue number4
Early online date22 Jan 2021
Publication statusPublished - Jul 2021


  • effect size
  • meta-analysis
  • ordinal versus quantitative predictions
  • verbal versus formal theories

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