Gower and Swansea West: New Boundaries 2018 Calculation

Gower and Swansea West: Overview

Projection: LAB seat

Implied MP at 2017:Geraint Davies  (LAB)
County/Area:West Glamorgan (Wales)
Electorate:80,177
Turnout:67.8%

PartyImplied 2017 VotesImplied 2017 Share
LAB28,80753.0%
CON20,98738.6%
Plaid2,0463.8%
LIB1,6953.1%
UKIP3850.7%
Green3300.6%
OTH1430.3%
LAB Majority7,82014.4%

See overview of other seats in Wales.



Introduction

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Gower and Swansea West 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.

Gower and Swansea West: Map

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

List of old seats forming part of Gower and Swansea West

The old seat(s) needed are:

Old seat: Gower

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

Old seat: GowerTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
SwanseaBishopston2,610Gower and Swansea West1,0547603926052091,940
SwanseaClydach5,525Swansea East1,5762,58253680950134,387
SwanseaFairwood2,218Gower and Swansea West1,0055707018039011,703
SwanseaGorseinon3,228Llanelli8181,365403801730102,444
SwanseaGower2,828Gower and Swansea West1,11483711227073082,171
SwanseaGowerton3,862Gower and Swansea West1,2621,5924943092093,047
SwanseaKingsbridge3,299Llanelli8141,3892837062082,338
SwanseaLlangyfelach3,803Swansea East1,3851,39343470840102,962
SwanseaLower Loughor1,734Llanelli4358154719078011,395
SwanseaMawr1,305Swansea East456479916099071,066
SwanseaNewton2,687Gower and Swansea West1,1995908221033041,929
SwanseaOystermouth3,151Gower and Swansea West1,3089685727072062,438
SwanseaPenclawdd2,852Gower and Swansea West8281,1722328062092,122
SwanseaPenllergaer2,466Swansea East7928082224036061,688
SwanseaPennard2,175Gower and Swansea West769553472201300141,535
SwanseaPenyrheol4,131Llanelli1,0911,98043500200083,372
SwanseaPontardulais4,616Llanelli1,4332,007445901150163,674
SwanseaUpper Loughor2,092Llanelli5348456223095031,562
SwanseaWest Cross5,023Gower and Swansea West1,5872,0236047079073,803
 Total59,605 19,46022,72893064001,669014945,576

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

Old seat: Swansea East

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

Old seat: Swansea EastTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
SwanseaBonymaen4,697Swansea East7571,983209024118002,992
SwanseaClydach101Swansea East183702030060
SwanseaCockett573Gower and Swansea West92188101134100345
SwanseaCwmbwrla5,337Gower and Swansea West9271,99113811534204003,409
SwanseaLandore4,472Swansea East6361,737737926133002,684
SwanseaLlangyfelach92Swansea East212702230055
SwanseaLlansamlet10,408Swansea East1,7973,9317117644272006,291
SwanseaMorriston11,532Swansea East2,0724,31716622259472007,308
SwanseaMynyddbach6,429Swansea East1,0652,4056812231166003,857
SwanseaPenderry7,146Swansea East9643,62532132107163005,023
SwanseaSt Thomas5,020Swansea East7902,066478930113003,135
 Total55,807 9,13922,3076251,0403601,6880035,159

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

Old seat: Swansea West

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

Old seat: Swansea WestTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
SwanseaCastle8,834Swansea East1,8184,65525801393580147,242
SwanseaCockett10,125Gower and Swansea West1,7383,8071940293490116,128
SwanseaDunvant3,353Gower and Swansea West8131,0947701245072,048
SwanseaKillay North1,892Gower and Swansea West60383570012700101,600
SwanseaKillay South1,846Gower and Swansea West405553350623001,022
SwanseaLandore132Swansea East206130020086
SwanseaMayals2,060Gower and Swansea West629525410623021,226
SwanseaSketty10,294Gower and Swansea West2,6883,2292330414010136,605
SwanseaTownhill5,617Gower and Swansea West7363,1438501943064,032
SwanseaUplands8,155Gower and Swansea West2,2304,37727301682150277,290
 Total52,308 11,68022,2791,26904321,52909037,279

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

New seat: Gower and Swansea West

The new seat of Gower and Swansea West is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Gower and Swansea West
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
SwanseaBishopston2,645Gower1,0547603926052091,940
SwanseaCockett9,351Swansea West1,7383,8071940293490116,128
SwanseaCockett573Swansea East92188101134100345
SwanseaCwmbwrla5,676Swansea East9271,99113811534204003,409
SwanseaDunvant3,125Swansea West8131,0947701245072,048
SwanseaFairwood2,324Gower1,0055707018039011,703
SwanseaGower2,961Gower1,11483711227073082,171
SwanseaGowerton4,156Gower1,2621,5924943092093,047
SwanseaKillay North2,443Swansea West60383570012700101,600
SwanseaKillay South1,561Swansea West405553350623001,022
SwanseaMayals1,872Swansea West629525410623021,226
SwanseaNewton2,632Gower1,1995908221033041,929
SwanseaOystermouth3,326Gower1,3089685727072062,438
SwanseaPenclawdd2,894Gower8281,1722328062092,122
SwanseaPennard2,094Gower769553472201300141,535
SwanseaSketty10,079Swansea West2,6883,2292330414010136,605
SwanseaTownhill6,154Swansea West7363,1438501943064,032
SwanseaUplands11,124Swansea West2,2304,37727301682150277,290
SwanseaWest Cross5,187Gower1,5872,0236047079073,803
 Total80,177 20,98728,8071,6953853302,046014354,393

And these are the implied results for 2017 for the new seat of Gower and Swansea West. 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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