Pew Research has not only helped shift the focus to a 21st Century paradigm, it also uses 21st century social scientific methods to study and track.*
But religious freedom is very difficult to measure because. How can you measure how freed someone is? So, Pew Research measures restrictions on religious freedom that come from governments AND from groups in society.
Each year since 2006, a team led by senior researcher Brian J. Grim at the Pew Research Center's Forum on Religion & Public Life has carefully studied the laws and constitutions for 198 countries and territories as well as human rights reports from major international sources – such as the United Nations, Amnesty International, Human Rights Watch, Human Rights First, the European Union and the U.S. State Department. Based on these sources, Pew Forum researchers count up and categorize each reported government restriction on religion and each reported social hostility involving religion, and use these data to create indexes.
There’s one important thing to keep in mind – these Pew Research studies do not place a value judgment on any particular restriction. In France, for instance, the government’s ban of the burqa – the Muslim full body covering – has considerable political and public support. In our study, this ban still counts as a restriction regardless of its popularity. In that way, Pew Research is like a thermometer. Their job is to measure, not to diagnose or suggest a treatment.
See Brian J. Grim's TEDx Talk - The Numbers of Religious Freedom - for more on the methodology and the findings. To take an "International Religious Freedom Literacy" quiz, see his blog.
* See the methodology of the Pew Forum’s 2009 report, “Global Restrictions on Religion,” for a discussion of the conceptual basis for measuring restrictions on religion.