Additional data sources
Statistical compendia such as Nationmaster (free web) are an excellent first place to look for statistics and sources of data when you don't know who might be interested in collecting the data you need.
Even if the compendium does not have the exact data you need, use it as a "guide to data sources" by studying the source notes.
The Data guide provides a list of compendia to help you start your search.
In the course of their work, governments, intergovernmental agencies (IGOs), nongovernmental agencies (NGOs), and academic scholars often produce data. Often (but not always), these data are made publicly available. We've provided a brief list of data producers to get you started.
There are numerous repositories of social science datasets. These are excellent starting points in your search for data. Some of the most important include:
These are some of the most frequently used sources by students searching for comparative political quantitative evidence.
The following are excellent guides to core political science data sources.
Visualization software lets you see otherwise hidden patterns in complex data.
This way of working with data is emerging and evolving rapidly. Check out this handy collection of data visualization tools from Carleton College.