By Stephen Fisher, 6th May 2021.
There is speculation about how well various new and small parties will do in today’s elections to the Scottish and Welsh Parliaments. Former SNP First-Minister Alex Salmond has recently established the Alba Party, while George Galloway has created Unity 4 All. Both are contesting regional list seats in Scotland. Meanwhile, Abolish the Welsh Assembly has come fourth, with at least 6% of the regional list vote, in all four polls for the Welsh Parliament (Senedd Cymru) since mid-April. Also, Reform-UK, the renamed Brexit Party, is fielding candidates in both countries. These are just some of the various contenders.
This post explains some of the complications in trying to figure out what share of the vote a party needs to get elected in these institutions. It ends up pointing to past experience as a guide and drawing comparison with and the electoral system for the Greater London Assembly (GLA).
TLDR: The experience of all five elections to the Scottish Parliament suggests that around 5.5% of a regional list vote is usually enough to win a seat. It would be rare, but not impossible, to miss out on a seat with 6%. Winning on 5.2% to 5.4% is not uncommon. The lowest D’Hondt ratio ever to yield a seat in Scotland was 4.6% (equivalent to a single party winning a seat on that share). That was in 2003 when the SNP won 5 seats, including 2 list seats, with 23.0% of the Mid Scotland and Fife list vote. For the Senedd, a share of around 6.5% in a region is likely to be enough, especially in North Wales and Mid and West Wales which have historically been more accessible to small parties. By comparison, the GLA has a 5% legal threshold, without which parties would get seats with 3.8% of the vote.
The Scottish Parliament has 129 seats. The electoral system is sometimes described as proportional, but it is significantly different from pure proportional representation. If it were close then a party would win a seat for roughly every 0.8% of the vote, since 100/129=0.8. More precisely, if all the seats were elected by the D’Hondt method of proportional representation a party would be guaranteed a seat with more than 100/(1+Number of seats) per cent of the vote, that is 100/130 = 0.77% of the vote. As we shall see that is much lower than what is actually required to get elected.
Continue reading What does it take to get elected in Scotland and Wales?
by Stephen Fisher.
Update 18.40, 4.5.17: I was mistaken as to the method for the Rallings and Thrasher projection, the details have now been corrected. Nothing about my forecast has changed.
This is definitely just for curiosity value only! Last week Roger Scully released the results of his Welsh Political Barometer survey which included Westminster and local election vote intention questions see here. The changes on the comparable survey from just before the last main round of Welsh local elections five years ago are presented in the first and third columns of the table below. Colin Rallings and Michael Thrasher did a seat projection based on the change from the actual 2012/3 local election vote share to the 2017 local-vote intention poll (Con +13, Lab -8, LD -1, PC +3), as discussed by Roger Scully here and listed in the second column of the table.
||Rallings & Thrasher
The final column of the table represents my attempt to translate the changes in the Westminster vote intention into changes in local election seats, similarly to the way I did for the English local elections. Regression analysis of local election results in Wales since 1995 shows strong linear relationships between votes and seats for each of the main parties, with the partial exception of the Liberal Democrats. On average the main parties have picked up around 16 extra seats for every percentage point extra in the overall share of the vote (just 12 for the Lib Dems).
If this relationship were to continue and if the changes in the opinion polls since 2012 were to be reflected in the results then the numbers of gains and losses would be much bigger than suggested in the Rallings and Thrasher projection. For instance Labour would be expected to lose 320 not just 130 seats.
By implication the geography of local election voting must be doing a lot of work to dampen the scale of gains and losses for the Conservatives and Labour parties in the Rallings and Thrasher projection. It would seem that there are a lot very safe Labour council seats in Wales and the system is extremely biased to Labour. The Rallings and Thrasher projection implies that the Labour would win with a 2 point lead over the Conservatives in votes, but more than twice as many seats (450 to 195). That would be extraordinarily unjust.
Projecting the changes in the Westminster vote intention on to seats with the regression method (final two columns) suggests the Conservatives will emerge (for the first time in a long time) with a substantial lead in both votes and seats.
Thanks to Eilidh Macfarlane for help with the data.
by Stephen Fisher
In the Scottish Parliament elections yesterday the SNP lost 6 seats and their majority because their share of the list vote fell by 2 points. They ended up with 49% of the seats from 42% of the vote. Meanwhile, at the Welsh Assembly elections Labour’s vote share dropped by 5.4% points but they lost just one seat, finishing with 48.3% of the seats from just 31.5% of the vote.
Why was the Welsh system so much more generous to Labour than the Scottish system was to the SNP? Continue reading How did Labour hold up so well in Wales?