Somerton and Frome: New Boundaries 2018 Calculation

Somerton and Frome: Overview

Projection: CON seat

Implied MP at 2017:David Warburton  (CON)
County/Area:Somerset (South West)
Electorate:78,638
Turnout:75.3%

PartyImplied 2017 VotesImplied 2017 Share
CON33,59056.7%
LIB12,58821.3%
LAB10,28117.4%
Green1,8493.1%
OTH9231.6%
CON Majority21,00235.5%

See overview of other seats in South West.



Introduction

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Somerton and Frome been in force at that time. The basic idea of the calculation is to look at the district council wards which make up the new seat, and estimate how they voted in 2017. This estimate is based on the recent local election results in those wards, with adjustments made to allow for different turnouts and different voting patterns for local and general elections.

In many cases, wards are divided between several old constituencies or between new constituencies. So the same ward may be shown more than once, but the electorate shown will reflect that ward sub-section.

Election results from a recent local election are given. This is usually the local election closest to 2015 from the period 2012-2015. For multiple-member wards, the votes shown are the sum of the votes cast for all candidates of each party. A negative number indicates candidate(s) elected unopposed.

Calculation method

There are two problems with using the raw (actual) local election results to imply general election results ward-by-ward. Firstly, turnout can be different between local and general elections, which means that the total number of local votes cast does not equal the number of votes cast in each old seat at the general election. To correct for this, we adjust the local votes to match the general election turnout. Each ward's result is scaled, whilst keeping constant the percentage support for each party, so that the total turnout adds up to the old seat's general election turnout. All wards in the old seat are assumed to have the same percentage turnout.

Secondly, even though we now have the correct number of votes in the old seat, the party totals will not match the general election result. Some parties do better at the local election than the general election, and others do vice versa. We call these strong and weak parties respectively. The next step is to transfer votes from strong parties to weak parties. This is done by taking votes proportionally away from strong parties and putting them in a transfer pool. For instance if a party got 12,500 local votes, but only 10,000 general election votes, it will lose 20% over all the wards. These votes in each ward will be put in the ward's transfer pool and allocated to the weak parties. Weak parties will get votes transferred to them in proportion to the votes they need over the old seat. For instance, if two weak parties need 4,000 and 1,000 votes respectively, the first party will get 80% of each ward's transfer pool and the second party will get 20% of each ward's transfer pool. The transfer of votes between parties is done using the Electoral Calculus Transition Model.

More details of the calculation formulas are available.

Somerton and Frome: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015, Map © OpenStreetMap contributors

List of old seats forming part of Somerton and Frome

The old seat(s) needed are:

Old seat: Somerton and Frome

The table shows the transfer-adjusted results for each ward in the old seat of Somerton and Frome, as well as showing which new seat each ward is in.

Old seat: Somerton and FromeTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
MendipAmmerdown1,810Somerset North East86119931806500221,465
MendipBeckington and Selwood1,573Somerton and Frome84317220805500181,296
MendipButleigh and Baltonsborough1,702Somerton and Frome82617430302500171,345
MendipColeford and Holcombe3,570Somerset North East1,782521419013300462,901
MendipCranmore, Doulting and Nunney1,744Somerton and Frome82120738402700181,457
MendipCreech1,755Somerton and Frome82122025805500201,374
MendipFrome Berkley Down3,265Somerton and Frome1,475535587012900422,768
MendipFrome College3,230Somerton and Frome1,389460687012100422,699
MendipFrome Keyford3,692Somerton and Frome1,258752750015400452,959
MendipFrome Market3,384Somerton and Frome1,416781745017200513,165
MendipFrome Oakfield1,791Somerton and Frome66437143007500271,567
MendipFrome Park3,453Somerton and Frome1,26969991106200412,982
MendipPostlebury1,637Somerton and Frome85619521806000191,348
MendipRode and Norton St Philip1,787Somerton and Frome90816025202700241,371
MendipThe Pennards and Ditcheat1,817Somerton and Frome86515326802300261,335
South SomersetBlackmoor Vale4,169Somerton and Frome2,05646572205900583,360
South SomersetBruton1,863Somerton and Frome1,06033328808500271,793
South SomersetBurrow Hill1,783Somerton and Frome86920324502500181,360
South SomersetCamelot2,042Somerton and Frome1,20421422203100281,699
South SomersetCary4,276Somerton and Frome1,906493808012600473,380
South SomersetCurry Rivel2,031Somerton and Frome1,07423119603100681,600
South SomersetIslemoor2,157Somerton and Frome1,12926128203000221,724
South SomersetLangport and Huish2,253Somerton and Frome91535736208100261,741
South SomersetMartock4,332Somerton and Frome2,02260678806500463,527
South SomersetMilborne Port2,188Somerton and Frome90329946503400271,728
South SomersetNorthstone2,339Somerton and Frome1,19228232703200241,857
South SomersetTower1,853Somerton and Frome1,03318718306200191,484
South SomersetTurn Hill2,244Somerton and Frome1,08122835003000271,716
South SomersetWessex4,089Somerton and Frome1,88564370106200493,340
South SomersetWincanton3,968Somerton and Frome1,850600648011100473,256
 Total77,797 36,23311,00113,32502,0470099163,597

The full details of these calculations are given on the Somerton and Frome seat details page. Click on "Show workings".

New seat: Somerton and Frome

The new seat of Somerton and Frome is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Somerton and Frome
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
MendipBeckington and Selwood1,721Somerton and Frome84317220805500181,296
MendipButleigh and Baltonsborough1,784Somerton and Frome82617430302500171,345
MendipCranmore, Doulting and Nunney1,936Somerton and Frome82120738402700181,457
MendipCreech1,824Somerton and Frome82122025805500201,374
MendipFrome Berkley Down3,674Somerton and Frome1,475535587012900422,768
MendipFrome College3,585Somerton and Frome1,389460687012100422,699
MendipFrome Keyford3,930Somerton and Frome1,258752750015400452,959
MendipFrome Market4,201Somerton and Frome1,416781745017200513,165
MendipFrome Oakfield2,081Somerton and Frome66437143007500271,567
MendipFrome Park3,961Somerton and Frome1,26969991106200412,982
MendipPostlebury1,789Somerton and Frome85619521806000191,348
MendipRode and Norton St Philip1,820Somerton and Frome90816025202700241,371
MendipThe Pennards and Ditcheat1,772Somerton and Frome86515326802300261,335
South SomersetBlackmoor Vale4,460Somerton and Frome2,05646572205900583,360
South SomersetBruton2,380Somerton and Frome1,06033328808500271,793
South SomersetBurrow Hill1,804Somerton and Frome86920324502500181,360
South SomersetCamelot2,254Somerton and Frome1,20421422203100281,699
South SomersetCary4,489Somerton and Frome1,906493808012600473,380
South SomersetCurry Rivel2,125Somerton and Frome1,07423119603100681,600
South SomersetIslemoor2,289Somerton and Frome1,12926128203000221,724
South SomersetLangport and Huish2,311Somerton and Frome91535736208100261,741
South SomersetMartock4,684Somerton and Frome2,02260678806500463,527
South SomersetMilborne Port2,294Somerton and Frome90329946503400271,728
South SomersetNorthstone2,465Somerton and Frome1,19228232703200241,857
South SomersetTower1,970Somerton and Frome1,03318718306200191,484
South SomersetTurn Hill2,279Somerton and Frome1,08122835003000271,716
South SomersetWessex4,434Somerton and Frome1,88564370106200493,340
South SomersetWincanton4,322Somerton and Frome1,850600648011100473,256
 Total78,638 33,59010,28112,58801,8490092359,231

And these are the implied results for 2017 for the new seat of Somerton and Frome. Please note that the wards used are those of 2015 in order to be consistent with those used by the Boundary Commissions.


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