Constituency-level volatility is more common that you might think

The highest vote swings occurred between 1965 and 1969, when the BDP’s vote share fell by 12.1% and the then new BNF gained 13.5% of the vote; between 1994 and 1999, when the BNF’s vote share fell by 11.1% and its offshoot, the BCP, gained 11.9% of the vote; and between 1989 and 1994, when the BDP’s vote share declined by 10.4% and that of the BNF’s grew by 10.1%. Aggregate vote swings of 10% or more were associated with party splits or economic downturns and labour unrest. Given the splits in the BDP, mixed economic conditions, and the disgruntlement of public sector workers, the BDP vote share is almost certain to decline in 2014 relative to 2009. An aggregate vote swing (i.e., away from the BDP) of 10% or more is quite possible. The outcome of the election, however, depends not only on the magnitude of the vote swing at the aggregate level but also on its distribution across constituencies.