Published on Let's Talk Development

Financial incentives in health: supply- vs. demand-side. Your help is needed!

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A blogpost on financial incentives in health by one of us in September 2015 generated considerable interest. The post raised several issues, one being whether demand-side financial incentives (like maternal vouchers) are more or less effective at increasing the uptake of key maternal and child health (MCH) interventions than supply-side financial incentives (variously called pay-for-performance (P4P) or performance-based financing (PBF)).

The four of us are now hard at work investigating this question — and related ones — in a much more systematic fashion. And we'd very much welcome your help.

A motivating chart from a quick-and-dirty analysis
The September 2015 blogpost highlighted just 3 recent evaluations – two PBF and one demand-side intervention. After the post, one of us did a quick literature trawl to unearth other studies that estimated impacts of demand- and supply-side side financial incentives on MCH outcomes in a credible way. The results were presented at a symposium on Innovations in Global Health Financing held at Erasmus University Rotterdam in November 2015. The evidence base included 5 PBF schemes and 7 demand-side schemes, including 3 voucher schemes and 4 CCT schemes. On average, the PBF schemes have much smaller impacts on the uptake of MCH interventions than the demand-side schemes – see the chart below.


Getting more systematic
The chart is food for thought, but raises lots of questions. Do the results hold for all studies on the topic? Are there systematic differences within each class of program? For example, do CCT schemes, on average, have larger impacts than voucher schemes? Do PBF schemes with some features have larger impacts than those without them? And are they so much more effective that on average they have larger impacts than demand-side interventions? What about cost-effectiveness?

We’re now well into a systematic review and meta-analysis aimed at answering these and related questions. The details are registered in the PROSPERO International Prospective Register of Systematic Reviews.

Here’s a quick summary of the boundaries of the study:

  • We’re focusing on MCH outcomes and uptake of MCH interventions, following the official and supplemental MDG indicators
  • We’re only looking at low- and middle-income countries
  • Under ‘supply-side incentive schemes’ we’re including PBF schemes that aim to improve MCH intervention coverage rates by financially incentivizing individual health workers or entire facilities
  • Under ‘demand-side incentive schemes’ we’re including schemes that are aimed at households. We include: CCT schemes with MCH components; MCH voucher schemes; contributory health insurance schemes covering MCH services; and reductions or removal of user fees for MCH services
  • Sometimes, of course, a program or intervention may combine supply- and demand-side incentives, combining, for example, PBF with vouchers. In such cases, studies may not necessarily be able to estimate the effect of each component; sometimes, they may, however 
  • We only include studies that estimate impacts using one or more of 4 methods. We’re including randomized experiments (individual and cluster level RCTs), as well as quasi-experimental studies using Regression Discontinuity, Instrumental Variables, and double- or triple-differences on repeated cross-sections or panel data
  • We’re excluding studies of non-randomized interventions using single-difference evaluation designs, such as cross-sectional with-and-without comparisons, before-and-after comparisons without a comparison group, and interrupted time-series analysis
  • We’ll be summarizing the studies in a qualitative fashion. But our main interest is in the meta-analysis we’re planning where we’ll be able to see how (and, hopefully, why) average effects differ between demand- and supply-side interventions, and within each class of intervention
We’d love your help
To make sure we’re coming up with meaningful results, we need to be sure we are including all the studies that meet our inclusion criteria. We’re systematically trawling through three types of database:
  • Previous systematic reviews – there have been a number, including 5 on PBF and no less than 13 on CCTs
  • Curated academic databases, like EconLit, EMBASE and SCOPUS
  • Google Scholar – we’re anticipating finding some that weren’t discovered in the two aforementioned databases

In addition, we’re searching through websites of donors and international organizations, and think tanks. We also stumble on studies while reading. Last, we get sent studies by people who know we’re doing this study.

And this is where you, the reader, comes in. If you know of studies that meet our criteria, we’d love to hear from you. You can just paste the details in as a comment below. Or if you prefer to do it privately, just send an email to

Thank you!


Adam Wagstaff

Research Manager, Development Research Group, World Bank

Damien de Walque

Lead Economist, Development Research Group, World Bank

Jed Friedman

Lead Economist, Development Research Group, World Bank

Sven Neelsen

Consultant, Development Research Group, World Bank

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