title: Chapter 4. Public health benefits.
abstract: This chapter introduces the concept of public health benefits in terms of the previously defined dimensions of the problem and of the available technology. Relevant to the measurement of direct health benefits is the clinical efficacy of the technology, estimated by means of controlled trials. Relevant to the measurement of indirect health benefits is the epidemiological effectiveness of the technology, which expresses the number of future cases prevented, as estimated from epidemiological simulation. "Aggregate health benefits" is defined as the sum of direct and indirect benefits. Problems of aggregation-in particular over time-are raised, and the concept of pure time preference is introduced. Procedures for computing estimates of efficacy and effectiveness levels, and of aggregate health benefits, are outlined.