Question

What are some of the other methodological challenges the economic analyst face when conducting evaluations of public health interventions?

Answer 1

Public health research is increasingly concerned with the assessment of value for money of large-scale public policies and interventions which impact on public health. Some of these large-scale public policies can incorporate characteristics of what economists call ‘public goods’. Public goods are goods that are available to everyone without exclusion, that can be enjoyed by all simultaneously and where one person’s use does not reduce the availability of the goods to others. Examples of public health interventions with characteristics of public goods include the introduction of bicycle lanes to encourage more active travel and the building of flood defences to protect homes and businesses against extreme weather. As recent articles have pointed out, the methods used by researchers to determine whether or not large-scale public policies offer value for money are currently inadequate, and when these policies involve characteristics of public goods, evaluations face even greater challenges.

The challenges faced are as below:

Costs of interventions

Although determining the costs of interventions is necessary in any economic evaluation, costing large-scale public health interventions can have particular challenges. Costs of large-scale public health interventions may be incurred by a range of agencies, making estimates of total costs trickyhe marginal cost of an additional concessionary journey can be estimated using a variety of methods, which can lead to different results, further complicating cost estimation. In addition to having costs shared by multiple agencies, large-scale public health interventions may also shift costs (for instance, from public service authorities to individual households) making total cost calculations even more problematic.

‘Wider’ effects of policies

Attribution of health and wider effects to large-scale interventions is also problematic. Large-scale interventions can occur at the same time as other changes, making it difficult to assess which specific changes in health outcomes result from the intervention. In complex environments there are often no obvious comparison or ‘control’ areas to help contextualise changes. Randomised controlled trial (RCT) designs are often not feasible (or necessarily appropriate) in evaluations of large-scale policies and so evaluations may need to rely on robust observational methods to attribute health and wider effects of policies.

Valuing outcomes

Although interest in economic evaluations of large-scale interventions within public health disciplines is relatively recent, there is a longer tradition of valuation in environmental, agricultural and resource economics. Policies with characteristics of public goods are common within these disciplines, and economists have produced good-practice guidelines on, for example, how to value wetlands and forest goods and services. Perhaps public health can learn from these disciplines to overcome some of the challenges of valuing large-scale policies.