In many public service settings, including health facilities, users offer unofficial “gifts” to frontline staff to build social relationships and secure better treatment. Rooted in social norms of reciprocity, this practice can fuel petty corruption, entrench inequality and distort access to essential services like healthcare. Traditional anti-corruption measures like training or controls are often insufficient in such contexts, but approaches that target social norms and behaviour change show promise.

We piloted a behavioural anti-corruption intervention in a public hospital in Dar es Salaam, Tanzania, in collaboration with the UK Behavioural Insights Team, the University of Dar es Salaam and the University of Utrecht. The intervention targeted social norms underpinning gift-giving and leveraged the social networks of health workers.

Using a peer-driven model, we recruited and trained anti-corruption champions from multiple professional groups. These champions shared messages discouraging gift acceptance in staff meetings and personal conversations.

Posters and desk signs reinforced the messages, stating that staff do not accept bribes. Desk signs also provided guidance on tactfully refusing gifts and appealed to professional ethics, with endorsement from hospital management and the national medical association.

Direct impact: measurable behaviour change Within eight weeks, the pilot recorded a 14–44 percent reduction in gift-giving intentions, attitudes and positive beliefs among hospital users. Posters and peer messaging proved more effective than written guidance on how to refuse gifts. Some beliefs – particularly around gifts given as “gratitude” after services – were more resistant to change.

Indirect impact: evidence and models for wider reform Beyond the measurable results, the pilot generated practical insights for tackling corruption rooted in social norms. It demonstrated the importance of clearly communicating that all forms of gift-giving constitute corruption, highlighting the negative consequences and using trusted peer networks and visible leadership support to reinforce behaviour change.

The intervention also showed the value of locally adapted, participatory approaches that complement traditional compliance measures. These lessons provide a foundation for applying similar social norms interventions in other hospitals and adapting the approach to address corruption risks in other public service sectors.

The Tanzania hospital pilot reflects the Basel Institute’s broader approach of linking research with practical anti-corruption action. Our Prevention, Research and Innovation team examines how corruption is shaped by social norms, informal practices and political realities, recognising that behaviour change is central to sustainable reform.

By piloting innovative interventions in real-world settings, we generate evidence on what works in practice. These insights inform anti-corruption strategies used by governments, development partners and civil society organisations, and support the design of behaviour-focused interventions alongside traditional compliance and enforcement measures.