Honesty oaths can help companies curb dishonest behavior

A new megastudy published in Nature Human Behaviour sheds light on effective ways to curb dishonest behavior.

Honesty oaths are the practice of having people assert that they are telling the truth or will not cheat when they sign a document. While honesty oaths have become a mainstay in business — think of the MBA Oath or the Dutch Banker’s Oath — studies of their effectiveness have garnered mixed results.

A team of global researchers, led by Janis Zickfeld and including IESE Business School’s Sebastian Hafenbrädl, set out to determine which kinds of oaths were most effective and why.

To do so, they tested 21 different kinds of honesty oaths among 21,500 participants in the U.S. and U.K. Participants played an incentivized tax evasion game in which they earned “income” in a numbers-sorting task but only paid “tax” on the income they self-reported, not what they actually earned.

Much like real-life income reporting, the game’s requirement to self-report income before taxation created a financial incentive for people to lie. Researchers found that, overall, participants maintained a tax compliance — the ratio between reported and actual income — of 86%.

Game iterations that included an honesty oath improved tax compliance by an average of 3.9 percentage points compared with not including an oath.

Of the types of oaths tested, the most effective referred to the specific behavior requested in the task at hand — in this case, honestly reporting final income from the sorting task. This intervention increased tax compliance by a whole 8.5 percentage points.

The second most effective oath specified that misreporting income was forbidden. In general, the most effective honesty oaths are those that specify procedures or make behaviors less ambiguous, suggesting that narrowing down what honesty means in a certain context increases honest behavior. This aligns with motivational psychology findings that reducing goal ambiguity increases goal achievement — something any experienced manager will recognize from designing team KPIs.

Honesty oaths that focused on social norms — for example, by mentioning how most other participants generally behave — were also moderately successful in reducing dishonesty.

However, oaths that appealed to a participant’s morality or social responsibility to others did surprisingly little to improve compliance, perhaps due to the private nature of the task. It seems these self-image or social-concern interventions might be best reserved for public declarations.

The study also tested the effectiveness of different forms and placements of honesty oaths, as well as their content. Having participants retype the oath rather than checking a box bolstered two of the oaths, including the most effective one that referred to the specific behavior.

Similarly, presenting honesty oaths directly before reporting income was more effective than including them before the initial task, well before reporting, but this effect was not statistically significant. That said, it did hold across different oath formulations, suggesting it might be helpful to link honesty oaths as closely as possible to the behavior to be influenced.

Exploratory analyses revealed that the location of participants also influenced effectiveness. On average, those based in the U.K. showed higher tax compliance than those in the U.S., perhaps reflecting differing levels of cultural trust toward public tax administration. Conversely, honesty oaths increased compliance more in the U.S. group, possibly because of this lower initial baseline. This suggests that understanding cultural context is key for those looking to implement honesty oaths in the workplace.

Female participants showed higher tax compliance on average, but oaths increased honesty more among male participants. Male participants, people who reported lower levels of general trust, and those who scored lower in measures for honesty and humility were more likely to misreport income in the absence of an honesty oath.

“In the workplace, honesty oaths may be especially useful in settings in which employees have to report information that is difficult to verify,” Hafenbrädl says. “You need to tailor to each specific context — avoiding general pledges and opting for oaths that spell out the particular behavior you want for the task at hand.”

How to design honesty oaths

When designing your own honesty oaths, consider these pointers:

• Spell out the behavior you want, e.g., “I commit to correctly reporting my income.”
• Explicitly define what you mean by words like “correctly” or “honestly,” by referring to previously established guidelines.
• Increase the involvement required to the commitment through retyping the oath (online) or signing it (offline).
• Place the oath in proximity to the target behavior, e.g., directly before a reporting task.
• Know your audience: targeting groups with typically higher dishonesty rates may have the largest impact.