No evidence that non-incentivized behavioral interventions effectively mitigate climate change

Hardaker, A., Asanov, I., Bartoš, F., & Bruns, S. B. (2026). No evidence that non-incentivized behavioral interventions effectively mitigate climate change after adjusting for publication bias. PNAS Nexus. pgag150. [Link]

≈ 0.000 Bias-adjusted effect (d)

63.5 BF₀₁ for null

91 Field studies

98.4% Pr(zero effect)

Null or counterintuitive results tend to go unpublished — so the literature can overstate the effectiveness of interventions such as nudges (Maier, Bartoš et al., 2022). We therefore reanalyzed 91 field studies on policy-appealing green behavioral interventions (Nisa et al., 2019) using Robust Bayesian Meta-Analysis (Bartoš et al., 2025)—after correcting for publication bias, the effect disappears. The data are 63.5× more consistent with zero effect than any effect at all.

Raw (unadjusted) Bias-corrected

← What did researchers report before correction? Press to find out.

Open circle = point estimate · Whiskers = 95% CI (raw) or CrI (corrected)

"After accounting for publication bias and model uncertainty, the data strongly favor a zero average effect. On average, behavioral interventions without incentives on households and individuals are unlikely to deliver material climate benefits."

Shifting climate policy toward incentives and structural interventions appears more promising than standalone behavioral nudges directed at citizens.

References

Nisa, C. F., Bélanger, J. J., Schumpe, B. M., et al. (2019). Meta-analysis of randomised controlled trials testing behavioural interventions to promote household action on climate change. Nature Communications, 10, 4545.

Maier, M., Bartoš, F., Stanley, T. D., Shanks, D. R., Harris, A. J. L., & Wagenmakers, E.-J. (2022). No evidence for nudging after adjusting for publication bias. PNAS, 119(31). https://doi.org/10.1073/pnas.2200300119

Bartoš, F., Maier, M., & Wagenmakers, E.-J. (2025). Robust Bayesian multilevel meta-analysis: Adjusting for publication bias in the presence of dependent effect sizes. PsyArXiv. https://doi.org/10.31234/osf.io/9tgp2_v1

Hardaker, A., Asanov, I., Bartoš, F., & Bruns, S. B. (2026). No evidence that non-incentivized behavioral interventions effectively mitigate climate change after adjusting for publication bias. PNAS Nexus. pgag150. [Link]