Recent economic crises have severely affected national and international efforts to reduce the high morbidity and mortality in developing countries. The repercussions of these crises are manifest in declining living standards, increasing poverty, malnutrition, ill health and death. Depressed commodity prices, the oil crisis of the late 1970s, and the ensuing balance of payment problems have weakened most governments' efforts to halt and eventually reverse the economic decline. In sub-Saharan Africa the effects of these crises have combined with an ever-increasing population to render ineffective the limited investments in health care.

There is nothing new about the belief that the spread of education with its influence on knowledge and outlook is a central force behind the demographic transition. In 1934 Penrose wrote: ‘when a community has gained the knowledge and acquired the habits necessary to reduce the death rate it will sooner or later gain the knowledge and acquire the habits necessary to reduce the birth rate. There may be time lag between the two processes, but both of them in a large share are the outcome of education’ (Penrose, 1934). It is thus surprising that investigation of the specific influence of parental education on the mortality of children in developing countries was neglected until Caldwell's (1979) analysis of survey data from Ibadan, Nigeria, which demonstrated that mother's education was a more decisive determinant of child survival than other family characteristics such as husband's occupation and education. Other studies followed this influential investigation. The greater contribution to mortality decline of educational advance compared to health care provision, it has been argued, is a contribution to the development versus medical technology debate (Mosley, 1985). Inevitably the beginnings of a counter-reaction may be discerned. Caldwell (1986) stressed that the influence of education should not be considered in isolation from the wider context, while Cooksey et al. (1986, unpublished) consider that the effect of maternal education may have been exaggerated.

Shortly after the first reports on the acquired immunodeficiency syndrome (AIDS) in the United States, it became clear that the disease was also particularly frequent in Haitians living in North America (Pitchenik et at., 1983; Curran et al., 1985) and in Africans seen in Europe for medical care (Katlama et al., 1984; Clumeck et al., 1984). Subsequently, surveys in Haiti and in Central Africa confirmed the occurrence of epidemic foci of AIDS in these areas (Pape et al., 1983; Malebranche et al., 1983; Piot et al., 1984; Van de Perre et al., 1984).

About two-thirds of the world's population live in areas where registration of vital statistics is unsatisfactory (Tietze, 1977), and in many countries such statistics from rural areas are unavailable or grossly underestimated (WHO, 1971). Most of the women who die in pregnancy and childbirth are poor and live in remote areas or city slums. Their deaths are accorded little importance and fail to enter registers.

Measuring the mortality impact of health interventions is not straightforward; there is now ample evidence of this. So why bother? Clearly, the utility, sensibility and feasibility of measuring the mortality impact of health interventions depend on many factors, which makes it difficult to offer simple prescriptions. The failure of those demanding measurement to appreciate this has led, on the one hand, to the proliferation of largely unsubstantiated claims on the achievements of health interventions and, on the other hand, to disillusionment about the prospects of demonstrating any impact on mortality. It is not difficult to account for the complexity of this area nor the current state of uncertainty. Progress has largely reflected developments in its three components—mortality measurement, health research and programme evaluation. It is thus not surprising to find the almost exclusive emphasis on measuring impact on infant and child mortality; in developing countries, child health is given a high priority in the allocation of resources by governments and donor agencies, and the techniques for estimating child mortality are generally more advanced.

The randomized controlled trial has become the standard basis for the evaluation of new therapeutic agents and procedures (and for measuring the protective efficacy of new vaccines or for assessing the value of screening procedures). Patients, who have met the criteria for eligibility and have agreed to participate in the trial, are allocated on a random basis to the alternative therapies under consideration. In order to avoid possible bias in the handling or assessment of these groups, a double blind procedure is preferred; the therapy given is not known to those who administer it, to those who assess the course of the disease thereafter, nor to the patients themselves. There is an extensive literature on clinical trials covering their logic and history, modern developments and the many complex, often controversial, issues that such trials have provoked. Not all issues have been fully resolved but by and large the principle, the practice and the ethical concerns of clinical trials are worked out and firmly established.

When assessing the effects of a programme one must first consider its objectives. When applied to the improvement of health, the word programme implies an intervention which is sustained, complex, dealing with more than a single aspect of one disease and usually going beyond simple provision of fixed curative facilities. How a programme is assessed will vary with the different components and the underlying purpose of the assessment. It is important to ask just what information is needed and whether or not it needs to be collected on a longitudinal basis.

The Gambia provides an unusual opportunity for the application of cost analysis to health due to a relatively long history of immunization and recent empirical research. The results should apply not only to immunization programmes but also to a variety of types of primary health care in developing countries. In particular, well-based estimates of the cost per case averted and the cost per death prevented by alternative health interventions should prove to be of widespread interest and usefulness.

A major Egyptian national programme for the control of diarrhoeal disease was launched in February 1984, with the aim of reducing the dehydration-specific mortality resulting from acute diarrhoea (52% of all infant deaths in 1979) and thus to reduce overall infant and childhood mortality.

The primary health care programme in Ghana has two objectives: (1) to achieve basic primary health care for 80% of the population of the country by 1990; (2) to attack the disease problems that contribute to 80% of the unnecessary deaths and disability afflicting Ghanaians, also by 1990.

Newborn infants are among those which generate the highest health care costs. For instance, the cost of hospital care until discharge was assessed at US $ 14,200 (Boyle et al., 1983) for babies weighing 1000–1499g at birth. The average hospital stay for a baby weighing less than 1500g at birth in 1981 was 100 days at an average daily cost of US$ 898 (Stahlman, 1984). Achievements in neonatal survival, especially of extremely low birth weight babies, have necessitated frequent revision of the definition of viability. However, modern neonatal intensive care cannot be regarded as appropriate for developing countries as it cannot be made accessible to all at an affordable cost.