To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer five original research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams rendered statistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowd-sourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.
Landy, Justin and Jia, Miaolei and Ding, Isabel and Viganola, Domenico and Tierney, Warren and Dreber, Anna and Johanneson, Magnus and Pfeiffer, Thomas and Ebersole, Charles and Gronau, Quentin and Ly, Alexander and van den Bergh, Don and Marsman, Maarten and Derks, Koen and Wagenmakers, Eric-Jan and Proctor, Andrew and Bartels, Daniel M. and Bauman, Christopher W. and Brady, William J. and Cheung, Felix and Cimpian, Andrei and Dohle, Simone and Donnellan, M. Brent and Hahn, Adam and Hall, Michael P. and Jiménez-Leal, William and Johnson, David J. and Lucas, Richard E. and Monin, Benoit and Montealegre, Andres and Mullen, Elizabeth and Pang, Jun and Ray, Jennifer and Reinero, Diego A. and Reynolds, Jesse and Sowden, Walter and Storage, Daniel and Su, Runkun and Tworek, Christina M. and Van Bavel, Jay and Walco, Daniel and Wills, Julian and XU, Xiaobing and Yam, Kai Chi and Yang, Xiaoyu and Cunningham, William A. and Schweinsberg, Martin and Urwitz, Molly and Uhlmann, Eric Luis, Crowd-sourcing Hypothesis Tests: Making Transparent How Design Choices Shape Research Results (July 17, 2020). In Press at Psychological Bulletin, 2020, Available at SSRN: https://ssrn.com/abstract=3654406 or http://dx.doi.org/10.2139/ssrn.3654406