Introduction

Assessment of the cost effectiveness of interventions designed to achieve the millennium development goals for health is complex. The methods must be capable of showing the efficiency with which current and possible new resources are used, and incorporating interactions between concurrent interventions and the effect of expanding coverage on unit costs.1 They should also allow valid comparisons across a wide range of interventions. Here we describe how the standardised cost effectiveness methods used in the World Health Organization's Choosing Interventions that are Cost Effective (CHOICE) project have tackled these issues.

Level of analysis

The analysis was performed for 14 regions classified by WHO according to their epidemiological grouping (table A on bmj.com). The regional results (except if not relevant to the disease area, for example, malaria) are available at www.who.int/choice, but the papers in this series give details for just two regions: Afr-E, which includes countries in sub-Saharan Africa with high child mortality and very high adult mortality, and Sear-D, which comprises countries in South East Asia with high child and adult mortality.2^–6

Definition and selection of interventions

The term intervention is defined to include any preventive, promotive, curative, or rehabilitative action that improves health. Interventions are analysed individually and then in combinations or packages that could be undertaken together (box 1), taking into account interactions in costs or effectiveness, or both.

Interventions were chosen for analysis either because they are commonly used or because disease control experts have advocated their introduction. In each case, some evidence was needed that the intervention could be effective. The list is not exhaustive, and excluding an intervention does not imply it is cost ineffective.

All interventions and combinations are assessed assuming they are implemented for 10 years starting in 2000, the year the Millennium Declaration was signed. Good policy making would then require a reassessment of …