This is NOT something that the blue team can rely on
One of the great hopes for the Tories just five months from the general election is that in the key battlegrounds with LAB, those where they won in 2010, incumbent MPs standing again will enjoy a bonus. Some commentators have put this at as much as 3% and then sought to do seat calculations based on this applying to every CON defence.
It is certainly true that first time CON incumbents standing again at GE10 did better than their party overall by an average of 1.8%. There was also a similar bonus for LAB first time incumbents but not on the same scale.
For this coming election we have something that has never existed before – a vast number of single seat constituency polls where a two stage question has been put. The first is a standard voting intention question – the second asks respondents to think specifically about their own constituency and the candidates who are likely to stand there.
This is aimed at teasing out possible tactical factors as well as incumbency elements.
What is striking going through each seat poll is the difference this can make. What I’ve done in the chart above is go through all the CON-held LAB facing polling from Lord Ashcroft over the past four months and counted up the changes the second question has and in which direction.
- Overall the Tories did a bit worse on the seat specific element but not by that much. My reading is that incumbency benefit is vulnerable to tactical voting which can sometimes negate it.
So it is hard to conclude based on the evidence there is that there is a first time incumbency bonus. It is certainly NOT something that sitting CON MPs are going to benefit from as of right.