1. Estimating the reproducibility of psychological science
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Yoram K. Kunkels, Dylan Selterman, Denise J. Humphries, Kristina G. Brown, David G. Dobolyi, David J. Johnson, Mark A. Roebke, Andy T. Woods, John Hodsoll, Marije van der Hulst, Alexander A. Aarts, Kim Kelso, Erin C. Westgate, James A. Grange, Jesse Chandler, Jenelle Feather, Annick Bosch, Olivia Devitt, Benjamin T. Brown, Megan M. Kyc, Štěpán Bahník, Alissa Melinger, Michael Conn, Rebecca S. Frazier, Marc Jekel, Sara Bowman, Michael J. Wood, Erica Baranski, Sining Wu, Milan Valášek, Anna E. Van't Veer, Jeanine L. M. Skorinko, Joeri Wissink, Sara Steegen, Michael C. Pitts, Douglas Gazarian, Steve N.H. Tsang, Matthew W. Kirkhart, Jennifer S. Beer, Nathali Immelman, Elizabeth Chagnon, Robbie C. M. van Aert, Maya B. Mathur, Magnus Johannesson, Joshua D. Foster, Frank J. Farach, Gandalf Nicolas, Ian S. Penton-Voak, Rebecca M. Goldberg, Sarah L. Thomas, Kathleen Schmidt, Stephanie C. Lin, Linda Cillessen, Belén Fernández-Castilla, Taru Flagan, René Schlegelmilch, Joanneke Weerdmeester, Cyril Pernet, Andreas Cordes, Onur Sahin, Jolanda J. Kossakowski, Samuel Shaki, David Santos, Sabine Scholz, Jeremy R. Gray, Frank Renkewitz, Key Jung Lee, Gillian M. Sandstrom, Marie K. Deserno, Melissa Vazquez, Ed Cremata, Rebecca Saxe, Manuela Thomae, Johannes M. Meixner, Emma Heikensten, Sylvia Eboigbe, Carmel A. Levitan, Natalia Vélez, James G. Field, Riet van Bork, Vivien Estel, Michèle B. Nuijten, Lin Lin, Kate M. Johnson, Bobby Den Bezemer, Jennifer A. Joy-Gaba, Francis Tuerlinckx, Frits Traets, Ilse Luteijn, Christopher R. Chartier, Denise C. Marigold, Denny Borsboom, Elizabeth Gilbert, Jeff Galak, Shannon P. Callahan, E. J. Masicampo, Thomas Talhelm, Chris H.J. Hartgerink, Patrick T. Goodbourn, Stephanie M. Müller, Taylor Nervi, Marcus Möschl, Katherine Moore, Wolf Vanpaemel, Seung K. Kim, Elizabeth Bartmess, Heather N. Mainard, Martin Voracek, Gea Hoogendoorn, Sean P. Mackinnon, Ryan Donohue, Kate A. Ratliff, Jin X. Goh, Anastasia E. Rigney, Andreas Glöckner, Marieke Vermue, Angela S. Attwood, Michelle A. DeGaetano, Nick Spencer, Heather Bentley, Nina Strohminger, Geneva T. Dodson, R. Nathan Pipitone, Hayley M. D. Cleary, Matt Motyl, Amanda L. Forest, Marcus R. Munafò, Marcel Zeelenberg, Susann Fiedler, Ann Calhoun-Sauls, Mallorie Miller, Anondah R. Saide, Ljiljana B. Lazarević, Hilmar Brohmer, Mallory C. Kidwell, Pranjal H. Mehta, Jessie Gorges, Russ Clay, Jeffrey R. Spies, Joanna E. Anderson, Johnny van Doorn, Ashley A. Ricker, Elizabeth W. Dunn, Erin L Braswell, Jamie DeCoster, Larissa Seibel, Matthias Lippold, Lutz Ostkamp, William B. Simpson, Cathy On-Ying Hung, Carina Sonnleitner, Emily M. Wright, Laura Dewitte, Koen Ilja Neijenhuijs, Tim Kuhlmann, Job Krijnen, Leah Beyan, Jesse Graham, Andrew M Rivers, Sacha Epskamp, Aamir Laique, Christopher J. Anderson, Peter Raymond Attridge, Eric-Jan Wagenmakers, Agnieszka Slowik, Michael C. Frank, Bryan Gorges, Alejandro Vásquez Echeverría, Gina Vuu, Giulio Costantini, Eskil Forsell, Michelangelo Vianello, Don van den Bergh, Anna Fedor, Courtney K. Soderberg, M. Brent Donnellan, Kayleigh E Easey, Shauna Gordon-McKeon, Raoul Bell, William J. Johnston, Brian A. Nosek, Ashlee Welsh, Melissa Lewis, Anna Dreber, Simon Columbus, Frank A. Bosco, Pia Tio, Joshua K. Hartshorne, Lars Goellner, Elisa Maria Galliani, Etienne P. Le Bel, Kellylynn Zuni, Olivia Perna, Kristi M. Lemm, Marco Perugini, Anniek M. te Dorsthorst, Hedderik van Rijn, Timothy M. Errington, Bennett Kleinberg, Vanessa C. Irsik, Frank Jäkel, Timothy Hayes, Mark Verschoor, Mark D. Cloud, Bethany Lassetter, Justin Goss, Paul J. Turchan, Gavin Brent Sullivan, Darren Loureiro, Jo Embley, Robert S. Ryan, Jovita Brüning, Jan Crusius, Joel S. Snyder, Larissa Gabrielle Johnson, Nicolás Delia Penna, Grace Binion, Calvin K. Lai, Gustav Nilsonne, Heather M. Fuchs, Angela Rachael Dorrough, Michelle Dugas, Johanna Cohoon, Minha Lee, Robert Krause, David Reinhard, Goran Knežević, Jason M. Prenoveau, Kristin A. Lane, Stanka A. Fitneva, Rima-Maria Rahal, Mathijs Van De Ven, Anup Gampa, Marcel A.L.M. van Assen, Jordan Axt, Felix Henninger, Misha Pavel, Daniel Lakens, Jeremy K. Miller, Sara García, Leslie Cramblet Alvarez, Colleen Osborne, Kai J. Jonas, Taylor Holubar, Stefan Stieger, Heather Barry Kappes, Felix Cheung, Daan R. van Renswoude, Catherine Olsson, Roel van Dooren, Tylar Martinez, Megan Tapia, Philip A. Gable, Cody D. Christopherson, Franziska Plessow, Roger Giner-Sorolla, Abraham M. Rutchick, Michael Barnett-Cowan, Mark J. Brandt, Rebecca A. Dore, Michael May, H. Colleen Sinclair, Georg Jahn, Daniel P. Martin, Fred Hasselman, Casey Eggleston, Nicole Mechin, Joshua J. Matacotta, Molly Babel, Franziska Maria Kolorz, Social & Organizational Psychology, IBBA, Clinical Psychology, EMGO+ - Mental Health, Social Networks, Solidarity and Inequality, Department of Social Psychology, Department of Methodology and Statistics, Aarts, A, Anderson, J, Anderson, C, Attridge, P, Attwood, A, Axt, J, Babel, M, Bahník, Š, Baranski, E, Barnett Cowan, M, Bartmess, E, Beer, J, Bell, R, Bentley, H, Beyan, L, Binion, G, Borsboom, D, Bosch, A, Bosco, F, Bowman, S, Brandt, M, Braswell, E, Brohmer, H, Brown, B, Brown, K, Brüning, J, Calhoun Sauls, A, Callahan, S, Chagnon, E, Chandler, J, Chartier, C, Cheung, C, Cd, Cillessen, L, Clay, R, Cleary, H, Cloud, M, Cohn, M, Cohoon, J, Columbus, S, Cordes, A, Costantini, G, Cramblet Alvarez, L, Cremata, E, Crusius, J, Decoster, J, Degaetano, M, Della Penna, N, den Bezemer, B, Deserno, M, Devitt, O, Dewitte, L, Dobolyi, D, Dodson, G, Donnellan, M, Donohue, R, Dore, R, Dorrough, A, Dreber, A, Dugas, M, Dunn, E, Easey, K, Eboigbe, S, Eggleston, C, Embley, J, Epskamp, S, Errington, T, Estel, V, Farach, F, Feather, J, Fedor, A, Fernández Castilla, B, Fiedler, S, Field, J, Fitneva, S, Flagan, T, Forest, A, Forsell, E, Foster, J, Frank, M, Frazier, R, Fuchs, H, Gable, P, Galak, J, Galliani, E, Gampa, A, Garcia, S, Gazarian, D, Gilbert, E, Giner Sorolla, R, Glöckner, A, Goellner, L, Goh, J, Goldberg, R, Goodbourn, P, Gordon McKeon, S, Gorges, B, Gorges, J, Goss, J, Graham, J, Grange, J, Gray, J, Hartgerink, C, Hartshorne, J, Hasselman, F, Hayes, T, Heikensten, E, Henninger, F, Hodsoll, J, Holubar, T, Hoogendoorn, G, Humphries, D, Hung, C, Immelman, N, Irsik, V, Jahn, G, Jäkel, F, Jekel, M, Johannesson, M, Johnson, L, Johnson, D, Johnson, K, Johnston, W, Jonas, K, Joy Gaba, J, Kappes, H, Kelso, K, Kidwell, M, Kim, S, Kirkhart, M, Kleinberg, B, Kneževic, G, Kolorz, F, Kossakowski, J, Krause, R, Krijnen, J, Kuhlmann, T, Kunkels, Y, Kyc, M, Lai, C, Laique, A, Lakens, D, Lane, K, Lassetter, B, Lazarevic, L, Lebel, E, Lee, K, Lee, M, Lemm, K, Levitan, C, Lewis, M, Lin, L, Lin, S, Lippold, M, Loureiro, D, Luteijn, I, Mackinnon, S, Mainard, H, Marigold, D, Martin, D, Martinez, T, Masicampo, E, Matacotta, J, Mathur, M, May, M, Mechin, N, Mehta, P, Meixner, J, Melinger, A, Miller, J, Miller, M, Moore, K, Möschl, M, Motyl, M, Müller, S, Munafo, M, Neijenhuijs, K, Nervi, T, Nicolas, G, Nilsonne, G, Nosek, B, Nuijten, M, Olsson, C, Osborne, C, Ostkamp, L, Pavel, M, Penton Voak, I, Perna, O, Pernet, C, Perugini, M, Pipitone, N, Pitts, M, Plessow, F, Prenoveau, J, Rahal, R, Ratliff, K, Reinhard, D, Renkewitz, F, Ricker, A, Rigney, A, Rivers, A, Roebke, M, Rutchick, A, Ryan, R, Sahin, O, Saide, A, Sandstrom, G, Santos, D, Saxe, R, Schlegelmilch, R, Schmidt, K, Scholz, S, Seibel, L, Selterman, D, Shaki, S, Simpson, E, Sinclair, H, Skorinko, J, Slowik, A, Snyder, J, Soderberg, C, Sonnleitner, C, Spencer, N, Spies, J, Steegen, S, Stieger, S, Strohminger, N, Sullivan, G, Talhelm, T, Tapia, M, te Dorsthorst, A, Thomae, M, Thomas, S, Tio, P, Traets, F, Tsang, S, Tuerlinckx, F, Turchan, P, Valášek, M, van 't Veer, A, Van Aert, R, van Assen, M, van Bork, R, van de Ven, M, van den Bergh, D, van der Hulst, M, van Dooren, R, van Doorn, J, van Renswoude, D, van Rijn, H, Vanpaemel, W, Vásquez Echeverría, A, Vazquez, M, Velez, N, Vermue, M, Verschoor, M, Vianello, M, Voracek, M, Vuu, G, Wagenmakers, E, Weerdmeester, J, Welsh, A, Westgate, E, Wissink, J, Wood, M, Woods, A, Wright, E, Wu, S, Zeelenberg, M, Zuni, K, Sociology/ICS, Experimental Psychology, Human Technology Interaction, Sociale Psychologie (Psychologie, FMG), Ontwikkelingspsychologie (Psychologie, FMG), and Brein en Cognitie (Psychologie, FMG)
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Research design ,Department Psychologie ,BF Psychology ,media_common.quotation_subject ,POWER ,Learning and Plasticity ,Reproducibility Project ,Q1 ,Experimental Psychopathology and Treatment ,Replication (statistics) ,Statistics ,TRUTH ,Psychology ,General ,Mathematics ,media_common ,Selection bias ,Replication crisis ,Behaviour Change and Well-being ,Multidisciplinary ,PUBLICATION ,Publication bias ,Reproducibility ,Confidence interval ,INCENTIVES ,PREVALENCE ,Meta-analysis ,REPLICABILITY ,REPLICATION ,Developmental Psychopathology ,FALSE - Abstract
IntroductionReproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. Scientific claims should not gain credence because of the status or authority of their originator but by the replicability of their supporting evidence. Even research of exemplary quality may have irreproducible empirical findings because of random or systematic error.RationaleThere is concern about the rate and predictors of reproducibility, but limited evidence. Potentially problematic practices include selective reporting, selective analysis, and insufficient specification of the conditions necessary or sufficient to obtain the results. Direct replication is the attempt to recreate the conditions believed sufficient for obtaining a previously observed finding and is the means of establishing reproducibility of a finding with new data. We conducted a large-scale, collaborative effort to obtain an initial estimate of the reproducibility of psychological science.ResultsWe conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. There is no single standard for evaluating replication success. Here, we evaluated reproducibility using significance and P values, effect sizes, subjective assessments of replication teams, and meta-analysis of effect sizes. The mean effect size (r) of the replication effects (Mr = 0.197, SD = 0.257) was half the magnitude of the mean effect size of the original effects (Mr = 0.403, SD = 0.188), representing a substantial decline. Ninety-seven percent of original studies had significant results (P < .05). Thirty-six percent of replications had significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams.ConclusionNo single indicator sufficiently describes replication success, and the five indicators examined here are not the only ways to evaluate reproducibility. Nonetheless, collectively these results offer a clear conclusion: A large portion of replications produced weaker evidence for the original findings despite using materials provided by the original authors, review in advance for methodological fidelity, and high statistical power to detect the original effect sizes. Moreover, correlational evidence is consistent with the conclusion that variation in the strength of initial evidence (such as original P value) was more predictive of replication success than variation in the characteristics of the teams conducting the research (such as experience and expertise). The latter factors certainly can influence replication success, but they did not appear to do so here. Reproducibility is not well understood because the incentives for individual scientists prioritize novelty over replication. Innovation is the engine of discovery and is vital for a productive, effective scientific enterprise. However, innovative ideas become old news fast. Journal reviewers and editors may dismiss a new test of a published idea as unoriginal. The claim that “we already know this” belies the uncertainty of scientific evidence. Innovation points out paths that are possible; replication points out paths that are likely; progress relies on both. Replication can increase certainty when findings are reproduced and promote innovation when they are not. This project provides accumulating evidence for many findings in psychological research and suggests that there is still more work to do to verify whether we know what we think we know.
- Published
- 2015
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