Semiocast — Methodology of Semiocast's Twitter political barometer

The political barometer’s ranking is based on the number of public tweets that mention each politician (among a list of more than 140 politicians) and for the first 20 politicians, we determine how many tweets are positive, neutral, criticisms or rejections.
Tweets about politicians do not necessarily mention their full name or their Twitter account. Users often call politicians with initials, nicknames or even joke hashtags. Wordplays are frequent. As a matter of fact, very few tweets mentioning politicians explicitly state their first and last names.
While top politicians, and especially the incumbent President Nicolas Sarkozy, are regularly mentioned in tweets in other languages from foreign news sources, conversations about French politicians mostly take place in French. As a result, political barometer’s ranking is only based on messages in French.
The occurrence of a given keyword such as the name of a politician does not necessarily mean this message is about a politician. Indeed, all top politicians are called by names or initials that are subject to polysemy. Polysemy is the property for a word to have multiple meanings. Disambiguation and polysemy filtering are required to count tweets that are actually about each politician.
Process description
The diagram below summarizes the process flow to produce political barometer figures.