The main aim of this project was to assess the stability of a measure of party identification based on a new question. The data generated in this study was compared with data based on the traditional <i>British Election Study</i> (BES)* measure of party identification, provided by Professor Harold Clarke of the University of North Texas. Users should note, however, the comparative data are not included in this dataset. Please see documentation for further details. The project also included some qualitative material from focus group work, which is also available alongside the quantitative element. *The BES series is held at the Data Archive under GN:33066. The dataset contains data on aggregate levels of party identification and vote intention for twelve months between February 1999 and January 2000. The party identification figures are based upon responses to the following question: 'Many people think of themselves as being Conservative, Labour, Liberal Democrat (or Nationalist), even if they don't always support that party. How about you? Generally speaking do you think of yourself as Conservative, Labour, Liberal Democrat (or Nationalist), or don't you think of yourself as any of these?'