Neath: New Boundaries 2018 Calculation

Neath: Overview

Projection: LAB seat

Implied MP at 2017:Christina Rees  (LAB)
County/Area:West Glamorgan (Wales)
Electorate:76,055
Turnout:68.0%

PartyImplied 2017 VotesImplied 2017 Share
LAB30,97159.8%
CON11,36422.0%
Plaid6,46912.5%
UKIP1,9423.8%
LIB1,0061.9%
LAB Majority19,60737.9%

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 Neath 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.

Neath: Map

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

List of old seats forming part of Neath

The old seat(s) needed are:

Old seat: Aberavon

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

Old seat: AberavonTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
Neath Port TalbotAberavon3,887Ogmore and Aberavon4281,891451170261002,742
Neath Port TalbotBaglan5,128Ogmore and Aberavon7902,156421480298003,434
Neath Port TalbotBriton Ferry East2,119Neath2271,03528560111001,457
Neath Port TalbotBriton Ferry West1,977Neath2211,1231756094001,511
Neath Port TalbotBryn and Cwmavon5,018Neath5872,267461300257003,287
Neath Port TalbotCoedffranc Central2,733Neath3601,28425820284002,035
Neath Port TalbotCoedffranc North1,752Neath24476655480102001,215
Neath Port TalbotCoedffranc West2,629Neath30077663510116001,306
Neath Port TalbotCymmer2,015Neath1821,0871453085001,421
Neath Port TalbotGlyncorrwg792Neath76404122303700552
Neath Port TalbotGwynfi895Neath85515132704400684
Neath Port TalbotMargam2,197Ogmore and Aberavon41684167610137001,522
Neath Port TalbotPort Talbot4,052Ogmore and Aberavon5061,899511180265002,839
Neath Port TalbotSandfields East4,850Ogmore and Aberavon6182,429411470272003,507
Neath Port TalbotSandfields West4,745Ogmore and Aberavon4822,471431340216003,346
Neath Port TalbotTai-bach3,557Ogmore and Aberavon3801,71735940182002,408
 Total48,346 5,90222,6615971,34502,7610033,266

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

Old seat: Neath

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

Old seat: NeathTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
Neath Port TalbotAberdulais1,780Neath32267322440185001,246
Neath Port TalbotAllt-wen1,707Neath30366120460164001,194
Neath Port TalbotBlaengwrach1,476Neath23759212390153001,033
Neath Port TalbotBryn-côch North1,665Neath38447717470241001,166
Neath Port TalbotBryn-côch South4,333Neath8391,531521130497003,032
Neath Port TalbotCadoxton1,249Neath222522372806500874
Neath Port TalbotCimla2,904Neath4301,30683610152002,032
Neath Port TalbotCrynant1,418Neath2305391537017100992
Neath Port TalbotCwmllynfell872Neath14137192306600610
Neath Port TalbotDyffryn2,338Neath41077535670350001,637
Neath Port TalbotGlynneath2,547Neath42495931700299001,783
Neath Port TalbotGodre'r graig1,210Neath2114411331015100847
Neath Port TalbotGwaun-Cae-Gurwen2,161Neath36284321580229001,513
Neath Port TalbotLower Brynamman984Neath135467102105500688
Neath Port TalbotNeath East4,758Neath6532,035701260448003,332
Neath Port TalbotNeath North2,960Neath4131,43134670129002,074
Neath Port TalbotNeath South3,679Neath5351,66153920235002,576
Neath Port TalbotOnllwyn882Neath134394132305400618
Neath Port TalbotPelenna853Neath1362881524013300596
Neath Port TalbotPontardawe4,040Neath7181,450441080508002,828
Neath Port TalbotResolven2,334Neath3401,01128650190001,634
Neath Port TalbotRhos1,834Neath37961721500218001,285
Neath Port TalbotSeven Sisters1,574Neath2776762043086001,102
Neath Port TalbotTonna1,850Neath29683119420105001,293
Neath Port TalbotTrebanos1,033Neath1893351229015800723
Neath Port TalbotYstalyfera2,250Neath36282827620297001,576
 Total54,691 9,08221,7147331,41605,3390038,284

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

New seat: Neath

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

New seat: Neath
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
Plaid
Votes
MIN
Votes
OTH
Votes
Total
Votes
Neath Port TalbotAberdulais1,818Neath32267322440185001,246
Neath Port TalbotAllt-wen1,743Neath30366120460164001,194
Neath Port TalbotBlaengwrach1,507Neath23759212390153001,033
Neath Port TalbotBriton Ferry East2,186Aberavon2271,03528560111001,457
Neath Port TalbotBriton Ferry West2,265Aberavon2211,1231756094001,511
Neath Port TalbotBryn and Cwmavon4,930Aberavon5872,267461300257003,287
Neath Port TalbotBryn-côch North1,701Neath38447717470241001,166
Neath Port TalbotBryn-côch South4,425Neath8391,531521130497003,032
Neath Port TalbotCadoxton1,276Neath222522372806500874
Neath Port TalbotCimla2,966Neath4301,30683610152002,032
Neath Port TalbotCoedffranc Central3,053Aberavon3601,28425820284002,035
Neath Port TalbotCoedffranc North1,820Aberavon24476655480102001,215
Neath Port TalbotCoedffranc West1,958Aberavon30077663510116001,306
Neath Port TalbotCrynant1,448Neath2305391537017100992
Neath Port TalbotCwmllynfell891Neath14137192306600610
Neath Port TalbotCymmer2,131Aberavon1821,0871453085001,421
Neath Port TalbotDyffryn2,388Neath41077535670350001,637
Neath Port TalbotGlyncorrwg827Aberavon76404122303700552
Neath Port TalbotGlynneath2,601Neath42495931700299001,783
Neath Port TalbotGodre'r graig1,236Neath2114411331015100847
Neath Port TalbotGwaun-Cae-Gurwen2,207Neath36284321580229001,513
Neath Port TalbotGwynfi1,027Aberavon85515132704400684
Neath Port TalbotLower Brynamman1,005Neath135467102105500688
Neath Port TalbotNeath East4,860Neath6532,035701260448003,332
Neath Port TalbotNeath North3,023Neath4131,43134670129002,074
Neath Port TalbotNeath South3,758Neath5351,66153920235002,576
Neath Port TalbotOnllwyn901Neath134394132305400618
Neath Port TalbotPelenna871Neath1362881524013300596
Neath Port TalbotPontardawe4,126Neath7181,450441080508002,828
Neath Port TalbotResolven2,384Neath3401,01128650190001,634
Neath Port TalbotRhos1,873Neath37961721500218001,285
Neath Port TalbotSeven Sisters1,608Neath2776762043086001,102
Neath Port TalbotTonna1,889Neath29683119420105001,293
Neath Port TalbotTrebanos1,055Neath1893351229015800723
Neath Port TalbotYstalyfera2,298Neath36282827620297001,576
 Total76,055 11,36430,9711,0061,94206,4690051,752

And these are the implied results for 2017 for the new seat of Neath. 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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