Data and statistical sources are created by or on behalf of governmental bodies as well has other organizations such as nonprofits, foundations, think-tanks, institution and businesses. Secondary data sources (data sets, tools, and statistics created by others) are a great resource for you to do your own analysis. The guide suggest both open data sources as well as proprietary licensed sources.
Note: these resources are starting points and should not be the only resources used for your research, analysis and synthesis.