Policy advocates are organizations that engage in research, provide analysis, and advocate for policy change related to a topic or issue. These groups may be described at nongovernmental organizations (NGO), intergovernmental organizations (IGO), or think tanks. 

Nongovernmental organizations are generally non-profits that are not affiliated with any governmental body. These groups include international charities, research institutes, churches, community-based organizations, lobby groups and professional associations. NGOs publish reports and provide statistics, which are available for free on their web sites. Examples of NGOs include Amnesty International, Save the Children, or Doctors without Borders.  

Think tanks are organizations (usually non-profit) which conduct public policy research and analysis. Examples of think tanks include Rand, Pew Research Center, or the Brookings Institution. 

Intergovernmental organizations generally consist of representatives of sovereign states pursuing common goals. IGOs are established by a formal instrument of agreement. Examples of IGOs include OECD, NATO, and the G-8. 

All of these organizations often publish reports and compile statistics, which are available for free on their web sites. Some think tanks and NGOs are non-partisan, but others do advocate for particular political positions and have the objective of influencing public policy. Be mindful of biases among any of the above described organizations.