About the data
Definitions
Data sources

About the data

The indicators in this table provide an overview of the conditions in which more than 5 billion of the world’s people live. Although not perfectly correlated with income or consumption per capita, they tend to tell a common story: on average, the residents of poor countries enjoy fewer amenities, lack basic skills, and suffer higher rates of illness and, consequently, live shorter lives. These indicators complement those in table 1.3, which measure progress toward international goals for social and economic development.

Except for the adult illiteracy rate, all of the indicators shown here appear elsewhere in the World Development Indicators. For more information about them, see About the data for tables 2.14 (access to safe water and sanitation), 2.16 (child malnutrition), 2.17 (life expectancy), and 3.7 (commercial energy use).

Literacy is difficult to define and to measure. The definition here is based on the concept of functional literacy—the ability to use reading and writing skills effectively in the context of the society. To measure literacy using such a definition requires census or sample survey measurements under controlled conditions. In practice, many countries estimate the number of illiterate adults from self-reported data or from estimates of school completion. Because of these problems, comparisons across countries—and even over time within countries—should be made with caution.

Definitions

• Life expectancy at birth is the number of years a newborn infant would live if prevailing patterns of mortality at the time of its birth were to stay the same throughout its life. • Prevalence of child malnutrition is the percentage of children under 5 whose weight by age is less than minus two standard deviations from the median of the reference population. • Access to sanitation is the percentage of the population with excreta disposal facilities that can effectively prevent human, animal, and insect contact with excreta. Suitable facilities range from simple but protected pit latrines to flush toilets with sewerage. To be effective, all facilities must be correctly constructed and properly maintained. • Access to safe water is the percentage of the population with reasonable access to an adequate amount of safe water (including treated surface water and untreated but uncontaminated water, such as from springs, sanitary wells, and protected boreholes). In urban areas the source may be a public fountain or standpipe located not more than 200 meters away. In rural areas the definition implies that members of the household do not have to spend a disproportionate part of the day fetching water. An adequate amount of safe water is that needed to satisfy metabolic, hygienic, and domestic requirements—usually about 20 liters a person a day. The definition of safe water has changed over time. • Adult illiteracy rate is the percentage of adults aged 15 and above who cannot, with understanding, read and write a short, simple statement about their everyday life. • Commercial energy use is measured by indigenous energy production (from all commercial sources) plus imports and stock changes less exports and international marine bunkers, stated in kilograms of oil equivalents per capita.

Data sources

The indicators here and throughout the rest of the book have been compiled by World Bank staff from primary and secondary sources. For most of the indicators shown in the tables in this section, the sources are cited in the notes to the tables referred to in About the data. Data on illiteracy are supplied by the United Nations Educational, Scientific, and Cultural Organization and published in its Statistical Yearbook (see Data sources for table 2.9).

THE WORLD BANK METHODOLOGY:

----- On External Debt

                Definitions

                Debt indicators

----- On WORLD DEVELOPMENT INDICATORS

Size of the economy

Quality of life

Development progress

Trends in long-term development

Long-term structural change

Key indicators for other economies

Population

Land use and deforestation

Growth of output

Credit, investment and expenditures

Integration with the global economy

               Back to Research Methods