Parliaments Day by Day: Parliamentary Careers in Comparison ꟷ Core Database

Identifying one's sample is the first step in the creation of any dataset. Samples for parliamentary research (political biographies, speech data, voting records, parliamentary proceedings) are no exception to this. Indeed, a reliable answer to questions like how many female parliamentarians were represented at which time in parliament, if the age of parliamentarians varies over time and how tenure in parliament has developed, all require an exact image of who was where when. Politicians, however, move around a lot. As such, who exactly is member of what parliament, faction and/or party changes frequently. To alleviate these difficulties, we present a new publicly available comparative database. This new large scope database contains complete, detailed day-by-day membership data for parliaments, factions and parties for all members of the national parliaments of Germany, Switzerland and the Netherlands between 1945 and 2017. This data has been set up to be highly accurate and have a high resolution. We took measures to make it as easy as possible to name-match these data to existing politician-level data. The integration with other data platforms like Parlgov, the manifesto-project and CLEA is also facilitated. Our database provides new means for parliamentary researchers to identify their samples. This information can be used to build new datasets and improve existing ones. Finally, we illustrate the value of high resolution membership data by regenerating often used aggregate measurements like the percentage of women in parliament, average age, seniority and legislative turnover. Our results reveal small, yet important biases and data errors in several, generally considered authoritative, sources for such aggregate statistics.