Many Labs 2: Investigating Variation in Replicability Across Samples and Settings
Authors: Klein Richard A. , Vianello Michelangelo , Hasselman Fred , Adams Byron G. , Adams Reginald B. , Alper Sinan , Aveyard Mark , Axt Jordan R. , Babalola Mayowa T. , Bahník Štěpán , Batra Rishtee , Berkics Mihály , Bernstein Michael J. , Berry Daniel R. , Bialobrzeska Olga , Binan Evans Dami , Bocian Konrad , Brandt Mark J. , Busching Robert , Rédei Anna Cabak , Cai Huajian , Cambier Fanny , Cantarero Katarzyna , Carmichael Cheryl L. , Ceric Francisco , Chandler Jesse , Chang Jen-Ho , Chatard Armand , Chen Eva E. , Cheong Winnee , Cicero David C. , Coen Sharon , Coleman Jennifer A. , Collisson Brian , Conway Morgan A. , Corker Katherine S. , Curran Paul G. , Cushman Fiery , Dagona Zubairu K. , Dalgar Ilker , Dalla Rosa Anna , Davis William E. , de Bruijn Maaike , De Schutter Leander , Devos Thierry , de Vries Marieke , Doğulu Canay , Dozo Nerisa , Dukes Kristin Nicole , Dunham Yarrow , Durrheim Kevin , Ebersole Charles R. , Edlund John E. , Eller Anja , English Alexander Scott , Finck Carolyn , Frankowska Natalia , Freyre Miguel-Ángel , Friedman Mike , Galliani Elisa Maria , Gandi Joshua C. , Ghoshal Tanuka , Giessner Steffen R. , Gill Tripat , Gnambs Timo , Gómez Ángel , González Roberto , Graham Jesse , Grahe Jon E. , Grahek Ivan , Green Eva G. T. , Hai Kakul , Haigh Matthew , Haines Elizabeth L. , Hall Michael P. , Heffernan Marie E. , Hicks Joshua A. , Houdek Petr , Huntsinger Jeffrey R. , Huynh Ho Phi , IJzerman Hans , Inbar Yoel , Innes-Ker Åse H. , Jiménez-Leal William , John Melissa-Sue , Joy-Gaba Jennifer A. , Kamiloğlu Roza G. , Kappes Heather Barry , Karabati Serdar , Karick Haruna , Keller Victor N. , Kende Anna , Kervyn Nicolas , Knežević Goran , Kovacs Carrie , Krueger Lacy E. , Kurapov German , Kurtz Jamie , Lakens Daniël , Lazarević Ljiljana B. , Levitan Carmel A. , Lewis Neil A. , Lins Samuel , Lipsey Nikolette P. , Losee Joy E. , Maassen Esther , Maitner Angela T. , Malingumu Winfrida , Mallett Robyn K. , Marotta Satia A. , Međedović Janko , Mena-Pacheco Fernando , Milfont Taciano L. , Morris Wendy L. , Murphy Sean C. , Myachykov Andriy , Neave Nick , Neijenhuijs Koen , Nelson Anthony J. , Neto Félix , Lee Nichols Austin , Ocampo Aaron , O’Donnell Susan L. , Oikawa Haruka , Oikawa Masanori , Ong Elsie , Orosz Gábor , Osowiecka Malgorzata , Packard Grant , Pérez-Sánchez Rolando , Petrović Boban , Pilati Ronaldo , Pinter Brad , Podesta Lysandra , Pogge Gabrielle , Pollmann Monique M. H. , Rutchick Abraham M. , Saavedra Patricio , Saeri Alexander K. , Salomon Erika , Schmidt Kathleen , Schönbrodt Felix D. , Sekerdej Maciej B. , Sirlopú David , Skorinko Jeanine L. M. , Smith Michael A. , Smith-Castro Vanessa , Smolders Karin C. H. J. , Sobkow Agata , Sowden Walter , Spachtholz Philipp , Srivastava Manini , Steiner Troy G. , Stouten Jeroen , Street Chris N. H. , Sundfelt Oskar K. , Szeto Stephanie , Szumowska Ewa , Tang Andrew C. W. , Tanzer Norbert , Tear Morgan J. , Theriault Jordan , Thomae Manuela , Torres David , Traczyk Jakub , Tybur Joshua M. , Ujhelyi Adrienn , van Aert Robbie C. M. , van Assen Marcel A. L. M. , van der Hulst Marije , van Lange Paul A. M. , van ’t Veer Anna Elisabeth , Vásquez- Echeverría Alejandro , Ann Vaughn Leigh , Vázquez Alexandra , Vega Luis Diego , Verniers Catherine , Verschoor Mark , Voermans Ingrid P. J. , Vranka Marek A. , Welch Cheryl , Wichman Aaron L. , Williams Lisa A. , Wood Michael , Woodzicka Julie A. , Wronska Marta K. , Young Liane , Zelenski John M. , Zhijia Zeng , Nosek Brian A. 
Published: December 2018

We conducted preregistered replications of 28 classic and contemporary published findings, with protocols that were peer reviewed in advance, to examine variation in effect magnitudes across samples and settings. Each protocol was administered to approximately half of 125 samples that comprised 15,305 participants from 36 countries and territories. Using the conventional criterion of statistical significance ( p < .05), we found that 15 (54%) of the replications provided evidence of a statistically significant effect in the same direction as the original finding. With a strict significance criterion ( p < .0001), 14 (50%) of the replications still provided such evidence, a reflection of the extremely high-powered design. Seven (25%) of the replications yielded effect sizes larger than the original ones, and 21 (75%) yielded effect sizes smaller than the original ones. The median comparable Cohen’s ds were 0.60 for the original findings and 0.15 for the replications. The effect sizes were small (< 0.20) in 16 of the replications (57%), and 9 effects (32%) were in the direction opposite the direction of the original effect. Across settings, the Q statistic indicated significant heterogeneity in 11 (39%) of the replication effects, and most of those were among the findings with the largest overall effect sizes; only 1 effect that was near zero in the aggregate showed significant heterogeneity according to this measure. Only 1 effect had a tau value greater than .20, an indication of moderate heterogeneity. Eight others had tau values near or slightly above .10, an indication of slight heterogeneity. Moderation tests indicated that very little heterogeneity was attributable to the order in which the tasks were performed or whether the tasks were administered in lab versus online. Exploratory comparisons revealed little heterogeneity between Western, educated, industrialized, rich, and democratic (WEIRD) cultures and less WEIRD cultures (i.e., cultures with relatively high and low WEIRDness scores, respectively). Cumulatively, variability in the observed effect sizes was attributable more to the effect being studied than to the sample or setting in which it was studied.