Thursday, May 13, 2010

What kind of a mandate do you need to be elected as an MP?

Not as big as you’d think! On average, you only need to persuade one in four voters in your NI constituency to support you. In some areas, less than one in five voters would be enough.

Most of the figures you see at election time talk about the percentage share of the vote, ie those who turned up at a polling station (or posted in their vote). But what about the percentage share of the eligible voters?

What kind of mandate do our local MPs achieve at the ballot box?

  • Willie McCrea was returned to Westminster as South Antrim’s MP with a mere 18.30% of the eligible electorate voting for him.
  • David Simpson topped the poll with 18.73% of Upper Bann’s eligible voters.
  • And 19.13% of people issued with a polling card in East Londonderry put an X in the box for Gregory Campbell.

At the other end of the scale ...

  • Despite having the fourth smallest turnout (54.91%), a whopping 38.37% of West Belfast voted for Gerry Adams.
  • Next best, 34.90% of the eligible electorate in North Down voted for Sylvia Hermon (though turnout in the constituency was the fifth smallest with only 55.26% of people coming out to vote).

The graph below is sorted by the size of the mandate and also shows the overall turnout. (Click on the graph to enlarge it.)

Bar chart showing percentage of eligible voters in a constituency who voted for the winning candidate along with an indication of the overall turnout

On average, the 18 MPs elected last week required just over 17,000 voters to give them their X, giving them an average mandate of 26.3% (with a 45.5% share of the votes actually cast).

(Cross-posted from Slugger O'Toole.)

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