Numerous academic papers have been written on attitudes towards European integration, many offering differing theories as to what will influence people most when it comes to voting on the EU constitution.
However, one Dutch academic, Claes H. de Vreese, has attempted to impose a rigid scientific discipline on studies, and has carried out a complex statistical analysis of existing data, in order to isolate the most important determinants.
In his paper, published by the Center for European Studies at Harvard University, he concludes that there are three key variables which influence voting behaviour. These are: attitudes on immigration; economic outlook; and sentiments towards the national government.
Basically, those who express negative views on immigration; who are pessimistic about economic prospects; and/or do not support their current government, are more likely to vote "no" in the referendum. Of the three issues, it seems that "immigration" is the most important.
Putting these factors together, de Vreese writes that the constitutional referendums "will result in a ‘no’ outcome under conditions of high levels of anti-immigration sentiments, pessimistic economic outlooks, and/or unpopularity of a government".
He concludes than any government calling for a referendum "must be very popular to compensate for the negative impact of economic pessimism and anti-immigration sentiments" in order to win the vote.
Although the findings have their limitations, in focusing in data obtained in Holland and Denmark, they would seem to have some resonance in the UK. The paper, therefore, is essential reading for referendum campaigners.