How to Induce Honesty: Results from a large-scale experiment

Everyday public behaviour is premised on honesty. But the imperative to be honest can conflict with self-interest. This conflict between public good and private gains is one of the largest sources of malignity in policy making, often resulting in non-compliance, inaction or outright sabotage by the target of policies. This paper is an empirical contribution toward linking such malignity to promoting honesty in public behaviour. We conducted a large field experiment involving 34,543 adults in nine countries to study what drives people to behave more honestly. In a three-arm randomised control trial, subjects reported the outcome from a single roll of an unbiased, six-sided dice. The higher the reported value, the more they earned. In two conditions (“private cash” and “private lottery”), the roll was observed only by the subject. In the third condition (“public cash”), subjects could opt to have their roll observed by the experimenter. A truthful report will yield an average value of 3.5. In the two “private” conditions, we found significant overreporting (from 3.76 in China to 4.43 in Mexico). In the “public cash” condition, 85% of subjects opted to be observed, with a resulting dramatic decline in overreporting (3.46 in Germany to 3.61 in Indonesia). We construct a model of honesty that accounts for behavioural regularities across the nine countries. Our study shows that, regardless of policy contexts, most people want to be seen as honest and a simple policy instrument such as opt-in monitoring is sufficient to induce them to behave honestly.