Research Steps in the Development and Evaluation of Public Health Interventions

Article excerpt

This century research has paved the way for major advances to be made in public health. More research is, however, required to develop new or improved public health interventions to deal with the common causes of morbidity, mortality or disability against a background of dwindling resources, especially in developing countries. In this article, we describe an approach to planning intervention-related research based on observations of research managed by a number of agencies and on personal experience in conducting or facilitating research in various countries. Considerable wastage and confusion occur because of poor understanding of the process of intervention development and evaluation. Nevertheless, goals can be clarified, arguments resolved, and outstanding research accomplished when reference is made to an explicit conceptual framework (Fig. 1). Progress is made from left to right in Fig. 1, from a description of the problem towards the testing and improvement of public health interventions. Below we describe the different steps that we have identified.

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The framework

1. Describe the problem

First, a given problem has to be confirmed to be a public health issue by carrying out basic epidemiological research to describe its nature and magnitude. Usually, the focus is on measuring the frequency of biological outcomes, such as death or disease or infections with a specific agent, in terms of population groups or geographical areas affected. An example of research of this kind is provided by the ongoing effort to document the burden of reproductive tract infections among women, following recent reports of very high rates of associated morbidity in certain areas, and a new commitment of the international health community to the concept of reproductive health. Sometimes, there is also interest in assessing the social or economic dimensions of the problem; in this way, studies have described the devastating impact of the acquired immunodeficiency syndrome (AIDS) pandemic on communities and their infrastructure in various parts of the world.

2. Identify risk factors

The next step is to carry out research to identify factors that are associated with the outcome of interest. Such risk factor studies can provide important clues to causal mechanisms and serve to specify the groups at greatest risk. This step may, if knowledge is sufficient, be combined with the first step. However, to be useful, risk factor studies need to be carefully designed, and guided by epidemiological theory. The unplanned observation of epidemiological associations (so-called "fishing expeditions") should be discouraged, since they often produce spurious results (1).

Most risk factor studies are observational. Occasionally, however, intervention studies may be necessary to establish that an identified risk factor is associated causally with the health outcome of interest, and not simply as a result of confounding or misclassification (2). This can be done through a controlled experiment which manipulates exposure to the risk factor. Such studies can be costly and difficult to conduct, and may, unless coupled to field trials of interventions, pose ethical problems. However, definitive evidence in controversial areas has been marshalled in this way. For example, the role of vitamin A deficiency in childhood mortality was only shown persuasively by randomized controlled trials that redressed the deficiency through vitamin A supplementation (3).

3. Explore the context and identify the determinants

This step focuses on describing the behavioural or social processes that lead to the risk factors. This step is critical because the majority of public health problems arise one way or another as a result of human behaviour, e.g. diarrhoeal diseases, cardiovascular diseases, lung cancer, acquired immunodeficiency syndrome (AIDS), and other sexually transmitted diseases (STDs). …