A barometer is a survey the questions of which are repeated, in the same terms, at specified intervals. Political barometers are often monthly whereas economic barometers can be quarterly. The great advantage of barometers is that they make it possible to analyse the opinion changes. No doubt, there is no other country in the world where so many surveys are released. About 500 surveys are issued per year.
Political polls are especially numerous, even compared to the United States, cradle of surveys.
Such wealth of surveys has three causes. The first one is probably the personalization of the French political life, which stems in great part from the universal suffrage of the presidential elections which encourages people to keep a close eye on the popularity rating of the various leaders. The symbiosis between the political science and research as well as the appetite of the French press for opinion polls may be two other reasons. Polls are only the tip of the opinion surveys iceberg. They form the obvious part of research, but a great majority of surveys carried out by research institutes come close to marketing and market research.