How to measure public demand for policies when there is no appropriate survey data?

Explanatory models accounting for variation in policy choices by democratic governments usually include a demand (by the public) and a supply (by the government) component, whereas the latter component is usually better developed from a measurement viewpoint. The main reason is that public opinion surveys, the standard approach to measuring public demand, are expensive, difficult to implement simultaneously for different countries for purposes of crossnational comparison and impossible to implement ex post for purposes of longitudinal analysis if survey data for past time periods are lacking. We therefore propose a new approach to measuring public demand, focussing on political claims made by nongovernmental actors and expressed in the news. To demonstrate the feasibility and usefulness of our measure of published opinion, we focus on climate policy in the time period between 1995 and 2010. When comparing the new measure of published opinion with the best available public opinion survey and internet search data, it turns out that our data can serve as a meaningful proxy for public demand.