Yeovil and Somerset South: New Boundaries 2018 Calculation

Yeovil and Somerset South: Overview

Projection: CON seat

Implied MP at 2017:Marcus Fysh  (CON)
County/Area:Somerset (South West)
Electorate:82,912
Turnout:71.6%

PartyImplied 2017 VotesImplied 2017 Share
CON32,36854.5%
LIB17,64529.7%
LAB7,41612.5%
Green1,0531.8%
OTH9191.5%
CON Majority14,72324.8%

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 Yeovil and Somerset South 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.

Yeovil and Somerset South: Map

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

List of old seats forming part of Yeovil and Somerset South

The old seat(s) needed are:

Old seat: Yeovil

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

Old seat: YeovilTransfer-adjusted Results
DistrictWardElectorate
2017		New SeatCON
Votes		LAB
Votes		LIB
Votes		UKIP
Votes		Green
Votes		NAT
Votes		MIN
Votes		OTH
Votes		Total
Votes
South SomersetBlackdown1,846Yeovil and Somerset South9108425101400171,276
South SomersetBrympton4,822Yeovil and Somerset South2,2124691,26404800404,033
South SomersetChard Avishayes1,806Yeovil and Somerset South72625342701900521,477
South SomersetChard Combe1,590Yeovil and Somerset South63814833504300151,179
South SomersetChard Crimchard1,847Yeovil and Somerset South73918156601800161,520
South SomersetChard Holyrood2,052Yeovil and Somerset South94223756802100241,792
South SomersetChard Jocelyn1,812Yeovil and Somerset South74518731401700651,328
South SomersetCoker4,098Yeovil and Somerset South1,84520584403400282,956
South SomersetCrewkerne6,092Yeovil and Somerset South2,3125011,331016300454,352
South SomersetEggwood1,911Yeovil and Somerset South7869442901600211,346
South SomersetHamdon2,040Yeovil and Somerset South83712351402000141,508
South SomersetIlminster4,404Yeovil and Somerset South1,7833521,040013200403,347
South SomersetIvelchester2,275Yeovil and Somerset South1,614197399032001592,401
South SomersetNeroche1,975Yeovil and Somerset South9638925601400211,343
South SomersetParrett1,855Yeovil and Somerset South7828239501400161,289
South SomersetSouth Petherton3,898Yeovil and Somerset South1,4142151,01303200352,709
South SomersetSt Michael's1,754Yeovil and Somerset South7599739901500141,284
South SomersetTatworth and Forton2,083Yeovil and Somerset South89513137901700601,482
South SomersetWindwhistle1,830Yeovil and Somerset South8698929301500181,284
South SomersetYeovil Central4,785Yeovil and Somerset South1,9398291,39206300454,268
South SomersetYeovil East4,656Yeovil and Somerset South1,7639671,40905800444,241
South SomersetYeovil South6,159Yeovil and Somerset South2,7298101,26906300494,920
South SomersetYeovil West4,910Yeovil and Somerset South2,1016751,38905400444,263
South SomersetYeovil Without5,851Yeovil and Somerset South2,0654011,169013100373,803
 Total76,351 32,3687,41617,64501,0530091959,401

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

New seat: Yeovil and Somerset South

The new seat of Yeovil and Somerset South is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Yeovil and Somerset South
DistrictWardElectorate
2017		Old Seat CON
Votes		LAB
Votes		LIB
Votes		UKIP
Votes		Green
Votes		NAT
Votes		MIN
Votes		OTH
Votes		Total
Votes
South SomersetBlackdown1,782Yeovil9108425101400171,276
South SomersetBrympton5,629Yeovil2,2124691,26404800404,033
South SomersetChard Avishayes2,062Yeovil72625342701900521,477
South SomersetChard Combe1,645Yeovil63814833504300151,179
South SomersetChard Crimchard2,122Yeovil73918156601800161,520
South SomersetChard Holyrood2,500Yeovil94223756802100241,792
South SomersetChard Jocelyn1,854Yeovil74518731401700651,328
South SomersetCoker4,126Yeovil1,84520584403400282,956
South SomersetCrewkerne6,075Yeovil2,3125011,331016300454,352
South SomersetEggwood1,878Yeovil7869442901600211,346
South SomersetHamdon2,106Yeovil83712351402000141,508
South SomersetIlminster4,672Yeovil1,7833521,040013200403,347
South SomersetIvelchester3,351Yeovil1,614197399032001592,401
South SomersetNeroche1,874Yeovil9638925601400211,343
South SomersetParrett1,799Yeovil7828239501400161,289
South SomersetSouth Petherton3,781Yeovil1,4142151,01303200352,709
South SomersetSt Michael's1,793Yeovil7599739901500141,284
South SomersetTatworth and Forton2,067Yeovil89513137901700601,482
South SomersetWindwhistle1,792Yeovil8698929301500181,284
South SomersetYeovil Central5,959Yeovil1,9398291,39206300454,268
South SomersetYeovil East5,919Yeovil1,7639671,40905800444,241
South SomersetYeovil South6,867Yeovil2,7298101,26906300494,920
South SomersetYeovil West5,949Yeovil2,1016751,38905400444,263
South SomersetYeovil Without5,310Yeovil2,0654011,169013100373,803
 Total82,912 32,3687,41617,64501,0530091959,401

And these are the implied results for 2017 for the new seat of Yeovil and Somerset South. 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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