Nudge

What is a nudge?

A nudge is a change in how a choice is presented or arranged that aims to influence behavior while keeping the alternatives available and avoiding a substantial change in financial incentives. Defaults, reminders, and the placement of options are common examples. A ban or a large financial penalty is not a nudge in this usual sense.

Evidence and limits

DellaVigna and Linos (2022) examined 126 randomized trials from two US nudge units involving more than 23 million people. The average effect was about 1.4 percentage points, versus 8.7 percentage points in the published academic comparison sample. This supports the possibility of modest effects in specific settings, not a general promise that nudges work.

Broad estimates are disputed. Mertens and colleagues’ meta-analysis (2022) reported an average benefit across choice-architecture studies, while Maier and colleagues’ reanalysis found that adjustment for publication bias removed clear evidence for an average effect in that dataset.

Getting someone enrolled is not the same as changing how they live. A measured change in enrollment or a one-time choice does not demonstrate a lasting habit or better wellbeing. Evaluate the particular intervention, the comparison, and the outcome. See nudge theory for a fuller discussion.