In a recent letter published in the Proceedings of the National Academy of Sciences, Maximilian Maier and colleagues argue there is an absence of evidence for the efficacy of nudging.
Nudging refers to indirect ways of influencing human decision making and behavior. Importantly, it involves making changes to the choice architecture presented to consumers, facilitating decision making that is deemed better by a higher authority. This is tied to libertarian paternalism, the idea that institutions can influence public behavior while respecting the public’s freedom of choice.
The “nudge,” which was popularized by Richard Thaler and Cass Sunstein, has been a revolutionary concept in behavioral economics. Despite this, some psychological scientists have questioned whether it is substantiated by empirical evidence.
A 2022 meta-analysis conducted by Stephanie Mertens and colleagues concluded that nudging was an effective tool for behavior modification. However, the authors also found significant publication bias, with a sensitivity analysis revealing a miniscule effect size in the case of severe publication bias.
In this letter, Maier and colleagues propose a correction technique known as “robust Bayesian meta-analysis” (RoBMA), which can circumvent the debate over the severity of publication bias. In applying this technique, the researchers concluded there was no evidence for an overall effect of nudging, as well as evidence against effective intervention via information or assistance. Using more precise estimates, the results revealed evidence against the efficacy of nudges in most domains.
They write, “However, all intervention categories and domains apart from ‘finance’ show evidence for heterogeneity, which implies that some nudges might be effective, even when there is evidence against the mean effect.”
“We conclude that the ‘nudge’ literature is characterized by severe publication bias. Contrary to Mertens et al , our Bayesian analysis indicates that, after correcting for this bias, no evidence remains that nudges are effective as tools for behavior change.”
The letter, “No evidence for nudging after adjusting for publication bias”, was authored by Maximilian Maier, František Bartoš, T. D. Stanley, David R. Shanks, Adam J. L. Harris, and Eric-Jan Wagenmakers.