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Updated: Sep 29, 2026

A Psychophysics Paradigm for the Collection and Analysis of Similarity Judgments
Published on: March 1, 2022
The SMD = .17 verdict-Comparative hypotheses, comparative trials and the real world
Christoph Flückiger1, Michael Barkham2, Juan Martín Goméz Penedo3
1Department of Psychology, University of Kassel, Kassel, Germany.
Abstract:
As in many areas of modern healthcare, major treatment breakthroughs are no longer easily achievable, even though optimism continues to fuel research. The real challenge is distinguishing random or trivial effects from small but meaningful ones. This is the central question of our umbrella review: What are the typical effect sizes generally expected when comparing two psychological therapies, and where might the boundary between random and meaningful effects lie in large studies? Our umbrella review focuses on the margins relevant to newer large-scale trials of over 1000 participants.
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