Table 4.
Nudge research by type of nudge.
| Percentage of effects associated with this category | Mean Cohen’ s d | Percentage of effects with p < 0.05 | Percentage of effects with p < 0.10 | Percentage of p-curves with evidential value (p < 0.05) | |
|---|---|---|---|---|---|
| Nudges that use automaticity | 15.3% | 0.521 | 72.7% | 78.6% | 100% |
| Nudges that do not use automaticity | 84.7% | 0.385 | 58.2% | 62.7% | 100% |
| Nudges that trigger system 1 | 72.1% | 0.468 | 63.2% | 66.7% | 100% |
| By arousing emotions | 29.3% | 0.326 | 54.9% | 59.7% | 100% |
| By harnessing biases | 20.0% | 0.515 | 64.3% | 65.0% | 100% |
| By simplifying the process | 24.4% | 0.539 | 71.4% | 73.9% | 100% |
| Nudges that engage system 2 | 41.6% | 0.346 | 60.9% | 65.1% | 100% |
| By encouraging joint evaluation | - | - | - | - | - |
| By creating opportunities for reflection | 22.4% | 0.329 | 65.0% | 68.7% | 100% |
| By prompting planning | 1.9% | - | - | - | - |
| By inspiring broader thinking | 14.7% | 0.396 | 49.5% | 54.2% | 100% |
| By increasing accountability | 1.2% | - | - | - | - |
| By emphasizing disconfirming evidence | - | - | - | - | - |
| By using reminders | 2.6% | - | - | - | - |
| Nudges that bypass both systems | 13.8% | 0.546 | 69.9% | 77.1% | 100% |
| By setting the default | 13.2% | 0.546 | 68.8% | 76.3% | 100% |
| By making automatic adjustments | 0.6% | - | - | - | - |
Percentage of effects associated with this category is a weighted mean, with an observation’s weight proportional to the inverse of the number of observations associated with the same article. Note that percentages add up to more than 100% because a given nudge can belong to more than one category and more than one subcategory. Mean Cohen’s d and percentage of effects with p < 0.05 (p < 0.10) are weighted means, with an observation’s weight proportional to the inverse of the number of non-missing observations associated with the same article and with the category named in the leftmost column. For the p-curve analysis, we randomly sample one observation per article and calculate the p-value for the null hypothesis that the random sample does not have evidential value. We repeat this procedure for 50 independent random samples and report the fraction of samples for which p < 0.05. We only report mean Cohen’s d, the percentage of effects with p < 0.05, the percentage of effects with p < 0.10, and the percentage of p-curves with evidential value if the discipline is associated with at least ten articles.