Bookmark and ShareNic Marks is a nef fellow and founder of the Centre for Well-being

I went to vote at the last general election with a heavy heart. I knew full well that my vote wouldn’t really count towards the result as I live in a safe seat.  Straight after voting I felt really angry about the whole system and while out walking my dog the idea came to me that I must be able to work out how much my vote didn’t count. Make a statistician angry and he’ll fight back with numbers.

To measure exactly how our system wastes so many people’s votes, I created the Voter Power Index. It’s based on the two main factors that determine how much or little power voters have.  The first is how marginal the constituency you happen to live in is: more marginality equals more power. The second is how many registered voters there are: fewer voters means each individual vote counts more.   The problem was how to estimate exactly how much power you have in a particular constituency.  I decided that if I looked at as many elections as possible I would be able to figure out what was the probability of a seat changing hands for different levels of marginality.  By creating a probabilistic model I could then estimate this probability for every constituency and hence calculate the Voter Power Index.

I must admit that when I first calculated the VPI, even I was staggered just how much most people’s votes don’t count.  It is clear that our current system is hugely inefficient at translating the will of the people into the result of a general election.  In fact the VPI allows us to put a number on the level of this inefficiency – the current system is only 25% efficient – whereas some sort of proportional representation system would approach 100% efficiency (for example the 2004 European Elections were about 96% efficient).

Not only is the system inefficient it is also chronically unjust. Voter Power is hugely unevenly distributed in the UK, with the most powerful 20% of voters having over 33 times more power than the least 20%.  Note that this is a far more uneven distribution than household income in the UK. Even before the redistribution through taxes and benefits – the richest 20 per cent of households ‘only’ earn 15 times as much as the poorest. After redistribution this inequity factor is reduced to under 4 times.

This year, as we approach another election, it’s more important than ever that ever that the scandal of our wasteful, unfair electoral system is exposed. That’s why it’s great that web developer Martin Petts has created a site that lets everyone quickly find out how much their vote is really worth.

The Voter Power Index shows that first past the post is profoundly undemocratic. It gives considerably more power to some voters than others. It betrays the fundamental principle of democracy:  one person one vote.  It is high time we changed the whole rotten system.

nef supports campaigns for democratic reform. Check out Power 2010 and the Electoral Reform Society.