Bridgwater and West Somerset: New Boundaries 2018 Calculation

Bridgwater and West Somerset: Overview

 Projection: CON seat 

Implied MP at 2017: Ian Liddell-Grainger  (CON)
County/Area: Somerset (South West)
Electorate: 73,223
Turnout: 73.4%

 Implied 2017 VotesImplied 2017 Share
CON29,39454.7%
LAB15,75929.3%
LIB5,86310.9%
UKIP1,7783.3%
Green9871.8%
CON Majority13,63525.4%

See overview of other seats in South West.

Bridgwater and West Somerset : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Bridgwater and West Somerset constituency, the 'South West' area and nation.

The political measures include the Left/Right and International/National axes (what does this mean).

The demographic measures are from the 2011 Census and include categories relating to national identity, economic activity, health and education. These categories are those which have the most relevance to political attitudes.

IndicatorSeatSouth WestAll GB
Party WinnerCONCONCON
Economic Position3° Right1° Right
National Position9° Nat1° Nat1° Int
EU Leave %62%53%52%
British Identity30%27%29%
Good Health50%47%48%
UK Born93%92%88%
Good Education47%40%39%
Good Job61%50%51%
High SEC60%52%51%
Average Age49.450.548.5
ABC1 Class63%54%53%

Bridgwater and West Somerset ranks #99 for "Leave", #275 for "Right" and #156 for "National" out of 600 new seats.

Indicators: Legend and Descriptions

Indicators : Legend and Descriptions

The colour scheme used in the table above is explained in the legend table below. The eight census indicators (British Identity, Good Health, UK Born, Good Education, Good Job, High SEC, Average Age and AB1 Class) all use the same 'Census' colour scheme indicating whether the area's level is above or below the national average.

TopicCat 1Cat 2Cat 3Cat 4Cat 5
Economic PositionVery LeftLeftCentristRightVery Right
National PositionVery IntInternationalCentristNationalVery Nat
EU Leave %Very RemainRemainBalancedLeaveVery Leave
CensusVery LowLowMediumHighVery High

Indicator definitions are given in terms of political data definitions or census categories:

IndicatorCensus
Question
Definition / Included Census Categories
Party WinnerArea party winner : actual election result or projected by Electoral Calculus
Economic PositionEconomic position between 100° Left and 100° Right, estimated by Electoral Calculus from political and demographic data.
National PositionNational position between 100° International and 100° National, estimated by Electoral Calculus from political and demographic data.
EU Leave %EU Referendum vote share for 'Leave' : actual result or estimate
British IdentityNational Identity (KS202)Those answering British, British-Other, or Scottish-British
Good HealthHealth (KS301)Those answering 'Very Good Health'
UK BornCountry of Birth (QS203)Those answering England, Northern Ireland, Scotland, Wales, GB Other, or UK Other
Good EducationHighest level of Qualification (QS501)Level 3 (A-level equivalent) or Level 4+ (degree equivalent)
Good JobOccupation (QS606)Occupation codes 1xx to 4xx (Managers, Professionals, Associates, and office workers)
High SECNS-SeC of Household Reference Person (QS609)National Statistics Socio-economic Classification from 1 to 4 (higher managers and professionals, lower managers and professionals, intermediate occupations, small employers and self-employed).
Average AgeAge (QS103)Average age of adults (18 years and above)
ABC1 ClassApproximated Social Grade (QS611)Approximated social grades A, B and C1

Bridgwater and West Somerset: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015

Introduction

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

List of old seats forming part of Bridgwater and West Somerset

The old seat(s) needed are:

Old seat: Bridgwater and West Somerset

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

Old seat: Bridgwater and West SomersetTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
SedgemoorBridgwater Dunwear4,034Bridgwater and West Somerset9731,101308236130002,631
SedgemoorBridgwater Eastover3,893Bridgwater and West Somerset1,0311,16924780120002,539
SedgemoorBridgwater Fairfax6,464Bridgwater and West Somerset1,7281,982387101210004,219
SedgemoorBridgwater Hamp4,532Bridgwater and West Somerset1,2151,5439310160002,958
SedgemoorBridgwater Victoria5,077Bridgwater and West Somerset1,4301,454158258130003,313
SedgemoorBridgwater Westover4,526Bridgwater and West Somerset1,1541,42728453360002,954
SedgemoorBridgwater Wyndham3,533Bridgwater and West Somerset1,4415712414930002,305
SedgemoorCannington and Wembdon3,922Bridgwater and West Somerset1,80332237124390002,559
SedgemoorEast Polden1,804Bridgwater and West Somerset807207943660001,177
SedgemoorHighbridge and Burnham Marine150Wells3733207100098
SedgemoorHuntspill and Pawlett1,867Wells79017219735230001,217
SedgemoorKing's Isle3,777Bridgwater and West Somerset1,65634438018680002,466
SedgemoorKnoll939Wells4246090353000612
SedgemoorNorth Petherton5,993Bridgwater and West Somerset2,37686158242490003,910
SedgemoorPuriton and Woolavington3,913Wells1,464640157245470002,553
SedgemoorQuantocks3,801Bridgwater and West Somerset1,65454718216810002,480
SedgemoorWest Polden1,990Bridgwater and West Somerset8912231216570001,298
West SomersetAlcombe2,340Bridgwater and West Somerset650464224152360001,526
West SomersetBrendon Hills1,034Bridgwater and West Somerset5605051111000673
West SomersetCarhampton and Withycombe967Bridgwater and West Somerset399108791630000632
West SomersetCrowcombe and Stogumber1,033Bridgwater and West Somerset4898862234000675
West SomersetDulverton and District2,140Bridgwater and West Somerset1,03514714017570001,396
West SomersetDunster and Timberscombe1,017Bridgwater and West Somerset41812773739000664
West SomersetGreater Exmoor943Bridgwater and West Somerset5303828118000615
West SomersetMinehead Central3,895Bridgwater and West Somerset1,434557355162340002,542
West SomersetMinehead North1,802Bridgwater and West Somerset66115614321140001,175
West SomersetMinehead South2,015Bridgwater and West Somerset65941616536380001,314
West SomersetOld Cleeve1,843Bridgwater and West Somerset7951961523560001,202
West SomersetPorlock and District1,967Bridgwater and West Somerset81817617966440001,283
West SomersetQuantock Vale1,766Bridgwater and West Somerset7942071155310001,152
West SomersetWatchet3,178Bridgwater and West Somerset95371230261460002,074
West SomersetWest Quantock890Bridgwater and West Somerset4138258522000580
West SomersetWilliton2,250Bridgwater and West Somerset62748428946230001,469
 Total89,295 32,10916,6646,3272,1001,06100058,261

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

New seat: Bridgwater and West Somerset

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

New seat: Bridgwater and West Somerset
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
SedgemoorBridgwater Dunwear3,401Bridgwater and West Somerset9731,101308236130002,631
SedgemoorBridgwater Eastover2,885Bridgwater and West Somerset1,0311,16924780120002,539
SedgemoorBridgwater Fairfax4,973Bridgwater and West Somerset1,7281,982387101210004,219
SedgemoorBridgwater Hamp3,566Bridgwater and West Somerset1,2151,5439310160002,958
SedgemoorBridgwater Victoria3,785Bridgwater and West Somerset1,4301,454158258130003,313
SedgemoorBridgwater Westover3,663Bridgwater and West Somerset1,1541,42728453360002,954
SedgemoorBridgwater Wyndham3,602Bridgwater and West Somerset1,4415712414930002,305
SedgemoorCannington and Wembdon3,529Bridgwater and West Somerset1,80332237124390002,559
SedgemoorEast Polden1,634Bridgwater and West Somerset807207943660001,177
SedgemoorKing's Isle4,022Bridgwater and West Somerset1,65634438018680002,466
SedgemoorNorth Petherton6,373Bridgwater and West Somerset2,37686158242490003,910
SedgemoorQuantocks3,614Bridgwater and West Somerset1,65454718216810002,480
SedgemoorWest Polden1,912Bridgwater and West Somerset8912231216570001,298
West SomersetAlcombe2,103Bridgwater and West Somerset650464224152360001,526
West SomersetBrendon Hills955Bridgwater and West Somerset5605051111000673
West SomersetCarhampton and Withycombe952Bridgwater and West Somerset399108791630000632
West SomersetCrowcombe and Stogumber955Bridgwater and West Somerset4898862234000675
West SomersetDulverton and District1,915Bridgwater and West Somerset1,03514714017570001,396
West SomersetDunster and Timberscombe954Bridgwater and West Somerset41812773739000664
West SomersetGreater Exmoor918Bridgwater and West Somerset5303828118000615
West SomersetMinehead Central2,842Bridgwater and West Somerset1,434557355162340002,542
West SomersetMinehead North1,653Bridgwater and West Somerset66115614321140001,175
West SomersetMinehead South1,946Bridgwater and West Somerset65941616536380001,314
West SomersetOld Cleeve1,717Bridgwater and West Somerset7951961523560001,202
West SomersetPorlock and District1,857Bridgwater and West Somerset81817617966440001,283
West SomersetQuantock Vale1,632Bridgwater and West Somerset7942071155310001,152
West SomersetWatchet2,834Bridgwater and West Somerset95371230261460002,074
West SomersetWest Quantock901Bridgwater and West Somerset4138258522000580
West SomersetWilliton2,130Bridgwater and West Somerset62748428946230001,469
 Total73,223 29,39415,7595,8631,77898700053,781

And these are the implied results for 2017 for the new seat of Bridgwater and West Somerset.


© 2017 Martin Baxter
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