The use of peer referral incentives to increase demand for voluntary medical male circumcision in Zambia

Publication Details

Zanolini, A, Bolton, C, Lyabola, LL, Phiri, G, Samona, A, Kaonga, A and Thirumurthy, H, 2016. The use of peer referral incentives to increase demand for voluntary medical male circumcision in Zambia. 3ie Impact Evaluation Report 52. New Delhi: International Initiative for Impact Evaluation (3ie).

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Arianna Zanolini, Carolyn Bolton, Lane-Lee Lyabola, Gabriel Phiri, Alick Samona, Albert Kaonga, Harsha Thirumurthy
Sub-Saharan Africa (includes East and West Africa)
Health Nutrition and Population, Social Protection
Gender analysis
Equity Focus
None specified
Evaluation design
Difference-in Difference (DID)
3ie Series Report
3ie Funding Window
Voluntary Medical Male Circumcision Thematic Window


The study evaluates the effectiveness of a piloted peer-referral intervention in which circumcision clients were offered financial incentives to refer their peers for male circumcision in order to increased VMMC demand.


Medical male circumcision is a promising HIV prevention tool in countries with generalised HIV epidemics, but demand creation interventions are needed as circumcision services are scaled-up. In Zambia, male circumcision has been among the main pillars of the country’s HIV prevention strategy. A major scale-up of voluntary medical circumcision (VMMC) services has occurred in the past five years. However, the prevalence of male circumcision continues to be low. The study evaluates an intervention that provided small financial incentives to circumcision clients who successfully referred their peers to also seek circumcision.  

Research questions

The primary aim for the study was to measure whether small financial incentives to circumcision clients who successfully referred their peers will lead to an increase of demand for VMMC among these peers.


Intervention design

The intervention was a peer-referral incentive programme to increase VMMC uptake in the Southern Province, Zambia. The intervention allowed men coming for male circumcision in randomly selected intervention clinics to refer up to five uncircumcised men in their social network and receive a monetary reward of 10 Kwacha (approximately US$2) for each referred man who undergoes circumcision. Men who came for circumcision received 5 referral vouchers that they could then provide to uncircumcised men in their social network. The men who underwent the circumcision procedure at the VMMC clinics could present the referral voucher to clinic staff. They retained the voucher until the referring person came to collect his referral payment.

Theory of change

The theory of change of this study posits that a peer-referral incentive may be a more effective catalyst to action than interpersonal communication interventions that is led by community health workers (CHWs) or mobilisers. Men who have undergone male circumcision may be more effective at promoting uptake in their social network than community health workers or others who are less well-known in the social network. Thus, the peer-referral incentive encourages already circumcised men to take on the role of a CHW or mobiliser who typically promotes VMMC.

Evaluation design

The evaluation follows a non-randomised control-intervention design that compares monthly numbers of circumcisions in each facility for the period before and during the intervention, using intervention and control facilities. The unit of data was monthly circumcision in each facility with a total of 28 facilities in the study. The evaluation used a quasi-experimental design with an estimated difference-in-difference (DID) model. Time dependent factors that are common in both treatment and control facilities were eliminated by the DID methodology. The outcome variable was the monthly number of male circumcisions in each facility, expressed as a linear function of facility fixed effects, time dummies and an interaction for facilities in the treatment group during the intervention period.

Main findings

The large majority of referred men declared that talking with the person who referred them had been very important for their decision to get circumcised. Most of the participants also declared that the referral incentive motivated them to refer more men. However, with the chosen referral amount, the incentive did not appear to be enough to significantly boost demand for male circumcision.

Cost efficiency analysis

The total cost of the study added up to 116,594 Kwacha for eight months. The 2014 exchange rate of 6 Kwacha per USD$1 was used to convert costs. This translated to a total of US$19,432 for eight months, or US$29,148 for 12 months.

Given the non-significant result of the evaluation, the cost-effectiveness was calculated as the total amount in US dollars for 12 months divided by the number of additional circumcisions in 12 months, assuming the intervention effects estimated above. Given an estimate of 7.6 additional circumcisions per month per facility due to the intervention, for six facilities an estimated 547 additional circumcisions would be performed over a 12-month period due to the intervention. As a result, an estimated cost of US$53.27 per additional circumcision was estimated. Due to the relatively small intervention effect, fixed costs of implementing the intervention were a much larger portion of total costs than variable costs associated with each additional circumcision.

Implications for policy and practice

While the evaluation did not produce a significant increase in VMMC demand, the number of referrals and the results from the questionnaire suggest that the incentive motivated men to try and refer men for male circumcision. The amount of the incentive and how it was delivered may have been the cause behind the lack of boost in demand. Thus, new incentive structures could be more effective and qualitative work may better inform the optimal amount for referral incentive.

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