For the purposes of this guide data will generally refer to "data sets," collections of data that you can manipulated, and statistics will generally refer to tables of static data. In reality it is all data. Many of the static tables of statistics may have been incorporated into a database. Advanced datasets (for example ICPSR, see below) will have code books that define the different variables.
In the US the transition between adminstrations has always been concerning for the preservation of data. The end of term archive attempts to identify preserve websites from previous adminstrations. If you can't find data that you think should exist, consult the Political Science Librarian for other ways to find US data.
Also, remember that the statistics and data that you may find may not have collected in a way that is useable for your research.Be careful adapting data without understanding how it was collected. Also some countries simply don't collect much data and what they do collect is not available to the public.
There are a lot of sources listed here. Note that you may not need data for your policy papers.
A tool for data download and visualization with social science data about U.S. states, counties, cities, and metropolitan statistical areas from more than 150 different government and non-government sources. It spans topics like employment, crime, religion, and education. The data series are standardized allowing you to easily find, compare, visualize, and export. Included are Data Planet Foundations and the Woods & Poole business module.
Learn how to use ISCPR. See the subject guide.
These are websites, electronic resources and databases where you can find local, national or international summary data (statistics) on different subjects. For more information see the Finding Data and Statistics guide.