The World Health Organization (WHO) publishes several statistical indicators within each of ten broad categories for each of its 194 member states. These statistical indicators are useful in monitoring global health conditions, as well as assisting in developing public health policy. The ten categories are: life expectancy and mortality; cause-specific mortality and morbidity; selected infectious diseases; health service coverage; risk factors; health workforce, infrastructure and essential medicines; health experience; health inequities; demographic and socioeconomic statistics; and health information systems and data availability.
The indicators of life expectancy and mortality are: life expectancy at birth; life expectancy at age 60; stillbirth (fetal death) rate; neonatal mortality (the probability of death occurring during the first 28 days of life); infant and under-five mortality rates (the probability of dying between birth and one and five years of age respectively); and adult mortality rate (the probability of dying between 15 and 60 years of age). The indicators for cause-specific mortality and morbidity include age-standardized mortality rates for the three broad categories of communicable diseases, non-communicable diseases, and injuries. In addition to providing age-standardized mortality rates for the adult population at ages 30-70 for all causes, the WHO publishes cause-specific age-standardized mortality rates for cancer, cardiovascular disease and diabetes, and chronic respiratory conditions. Other cause-specific indicators include mortality rates and incidence rates and prevalence per 100,000 population for Malaria, Tuberculosis, and HIV/AIDS.
The selected infectious diseases for which the WHO publishes the number of reported cases include cholera, diphtheria, influenza, encephalitis, leprosy, malaria, measles, meningitis, mumps, pertussis, plague, poliomyelitis, rubella, tetanus, tuberculosis, and yellow fever. Despite ongoing efforts to enhance disease surveillance and response, many countries face challenges in accurately identifying, diagnosing and reporting infectious diseases due to remoteness of communities, lack of transport and communication infrastructures, and a shortage of skilled health-care workers and laboratory facilities to ensure accurate diagnoses. Some diseases with very small initial case numbers can potentially cause devastating epidemics, and so mandatory reporting is essential.
Health service coverage indicators reflect the extent to which people in need actually receive important health interventions such as reproductive-health services, provision of skilled care to women during pregnancy and childbirth, immunization to prevent common childhood infections, vitamin A supplementation in children, and the prevention and treatment of disease in children, adolescents and adults. Certain preventable risk factors that are associated with increased mortality and morbidity include unsafe water and lack of sanitation, low birth weight, poor infant-feeding practices, childhood under-nutrition, diabetes, hypertension, obesity, harmful consumption of alcohol, use of tobacco, and unsafe sex. Data on the resources available to health systems are essential in enabling governments to determine how best to meet the health-related needs of their populations. Such resources include physicians, nurses and midwives, other health-care workers, hospital and psychiatric beds, and radiotherapy units, as well as access to essential medicines. Health expenditure indicators include: total expenditure on health as a percentage of gross domestic product; general government expenditure on health as a percentage of total expenditure on health; private expenditure on health as a percentage of total expenditure on health; general government expenditure on health as a percentage of total government expenditure; external resources for health as a percentage of total expenditure on health; social security expenditure on health as a percentage of general government expenditure on health; out-of-pocket expenditure as a percentage of private expenditure on health; private pre-paid plans as a percentage of private expenditure on health; per capita total expenditure on health; and per capita government expenditure on health.
Health indicators are generally reported based on national averages. However, the statistical distributions of health data within countries and between population subgroups are also important. Such data identify health inequities that arise from socioeconomic factors, such as education, occupation, household income, location, ethnicity and gender. Certain demographic and socioeconomic factors are, in fact, major determinants of health. Basic data, such as population size, growth and degree of urbanization, crude birth and death rates, adult literacy, and per capita gross national income, have intrinsic value, but are also relevant in making other statistics comparable across countries; indicators for rates of disease incidence and prevalence and mortality require reliable population-based measures of exposure in their computation. Census and civil registration systems provide information on vital events occurring in the whole population. However, many less-developed countries have incomplete registration systems or even no registration system at all. For this reason, well-designed household surveys are often utilized as a means of gathering data for the purpose of compiling specific statistical indicators. The majority of the health-related indicators for the United Nations Millennium Development Goals are derived from survey data. The technical expertise of statisticians in designing household surveys for low and middle-income countries enables the WHO to compile and publish its annual comprehensive set of statistical indicators for member states.