The World Bank’s statistical data for over 550 development indicators and time series data from 1960-2006 for over 200 countries and 18 country groups. Data includes social, economic, financial, natural resources, and environmental indicators.
The link above is to the library’s subscription version of the database. Much of it is also available free online, but the interface is less reliable (especially for downloading).
Time frame: 1960-2006, though there is not complete data for every country in every series for every year. Always check for missing data before determining that WDI will have what you need.
Good for: reliable, highly sited comparative data for countries and regions
Documentation: For data documentation, see the reference book: World Development Indicators, in the library at Ref HC 59.15 .W656, or online.
More on documentation.
The WDI can be difficult to use if you are unfamiliar with the concepts being measured. Even when you are familiar with them, the particular ways in which the World Bank measures its variables must be known before the data can be used meaningfully. To learn what the World Bank means by “school enrollment” (i.e., does it include all schools or just public schools? Does it include home schoolers? How much of the school year does a child need to attend to be considered enrolled?) or the difference between the Fisher, Paasche and the Laspeyres Price Indices, consult one of the following:
Statistical considerations: Consult the World Bank Statistical Manual when using data from the WDI and other sources of comparative national data.
Definitions: Within the WDI database, on the results page, the series names are linked. The links go to full definitions. Also, there is a link on the page leading to more detailed documentation.
Definitions: Possibly the easiest way to learn definitions of the WDI data series is by using the book: World Development Indicators (yep, it’s title is the same as the data, which can be confusing). It is available in paper and online, but the online version requires a lot of clicking.