I Solemnly Swear I'm Up To Good: A Megastudy Investigating the Effectiveness of Honesty Oaths on Curbing Dishonesty

Janis Zickfeld (1) , Karolina Scigala (1) , Christian Elbaek (1) , John Michael (2) , Mathilde Tønning Tønnesen (1) , Gabriel Levy (3) , Shahar Ayal (4) , Isabel Thielmann (5) , Laila Nockur (1) , Eyal Peer (6) , Valerio Capraro (7) , Rachel Barkan (8) , Simen Bø (9) , Štěpán Bahník (10) , Daniele Nosenzo (1) , Ralph Hertwig (11) , Nina Mazar (12) , Alexa Weiss (13) , Ann-Kathrin Koessler (14) , Ronit Montal-Rosenberg (6) , Sebastian Hafenbrädl (15) , Yngwie Asbjørn Nielsen (1) , Patricia Kanngiesser (16) , Simon Schindler (17) , Philipp Gerlach (18) , Nils Köbis (11) , Nicolas Jacquemet (19, 20) , Marek Albert Vranka (21) , Dan Ariely (22) , Jareef Martuza (23) , Yuval Feldman (24) , Michal Bialek (25) , Jan Kristian Woike (16) , Zoe Rahwan (11) , Alicia Seidl (26) , Eileen Chou (27) , Agne Kajackaite (2) , Simeon Schudy (28) , Ulrich Glogowsky (29) , Anna Czarna (30) , Stefan Pfattheicher (1) , Panagiotis Mitkidis (1)

1 Aarhus University [Aarhus]
2 UNIMI - Università degli Studi di Milano = University of Milan
3 NTNU University Museum [Trondheim]
4 RUNI - Reichman University [Herzliya]
5 Max-Planck-Institut
6 HUJ - The Hebrew University of Jerusalem
7 UNIMIB - Università degli Studi di Milano-Bicocca = University of Milano-Bicocca
8 BGU - Ben-Gurion University of the Negev
9 Norwegian School of Economics and Business Administration
10 VSE - Prague University of Economics and Business
11 Max Planck Institute for Human Development
12 BU - Boston University [Boston]
13 Universität Bielefeld = Bielefeld University
14 Leibniz Universität Hannover=Leibniz University Hannover
15 IESE Business School
16 University of Plymouth
17 Federal University of Applied Administrative Services, Berlin
18 Fresenius University, Hamburg
19 PSE - Paris School of Economics
20 CES - Centre d'économie de la Sorbonne
21 Charles University, Faculty of Education [Prague]
22 Duke University [Durham]
23 Department of Strategy and Management, Norwegian School of Economics
24 Bar-Ilan University [Israël]
25 UWr - University of Wrocław [Poland]
26 Max Planck Institute for the Study of Crime, Security and Law = Max Planck institut zur erforschung von kriminalität sicherheit und recht
27 University of Virginia
28 Universität Ulm - Ulm University [Ulm, Allemagne]
29 JKU - University of Linz - Johannes Kepler Universität Linz
30 UJ - Uniwersytet Jagielloński w Krakowie = Jagiellonian University

Dishonest behaviors such as tax evasion impose significant societal costs. Ex-ante honesty oaths—commitments to honesty before action—have been proposed as useful interventions to counteract dishonest behavior, but the heterogeneity in findings across operationalizations calls their effectiveness into question. We tested 21 honesty oaths (including a baseline oath)—proposed, evaluated, and selected by 44 expert researchers—and a no-oath condition in a megastudy in which 21,506 UK and US participants played an incentivized tax evasion game. Of the 21 interventions, 10 significantly improved tax compliance by 4.5 to 8.5 percentage points, with the most successful nearly halving tax evasion. Limited evidence for moderators was found. Experts and laypeople failed to predict the most effective interventions, but experts’ predictions were more accurate. In conclusion, honesty oaths can be effective in curbing dishonesty but their effectiveness varies depending on content. These findings can help design impactful interventions to curb dishonesty.

Mots clés: honesty oath; dishonesty; tax compliance; nudging; unethical behavior

Domaines: Economies et finances; Psychologie et comportements

Janis Zickfeld, Karolina Scigala, Christian Elbaek, John Michael, Mathilde Tønning Tønnesen, et al.. I Solemnly Swear I'm Up To Good: A Megastudy Investigating the Effectiveness of Honesty Oaths on Curbing Dishonesty. 2024. ⟨halshs-04555561⟩