Bridgnorth and The Wrekin: New Boundaries 2018 Calculation

Bridgnorth and The Wrekin: Overview

 Projection: CON seat 

Implied MP at 2017: Mark Pritchard  (CON)
County/Area: Shropshire (West Midlands)
Electorate: 73,850
Turnout: 74.1%

 Implied 2017 VotesImplied 2017 Share
CON33,33660.9%
LAB16,62130.4%
LIB2,3734.3%
UKIP1,3712.5%
Green7121.3%
OTH3400.6%
CON Majority16,71530.5%

See overview of other seats in West Midlands.

Bridgnorth and The Wrekin : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Bridgnorth and The Wrekin constituency, the 'West Midlands' 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.

IndicatorSeatWest MidlandsAll GB
Party WinnerCONCONCON
Economic Position12° Right2° Right
National Position14° Nat9° Nat1° Int
EU Leave %60%59%52%
British Identity28%28%29%
Good Health48%45%48%
UK Born95%89%88%
Good Education39%35%39%
Good Job53%48%51%
High SEC53%46%51%
Average Age49.848.748.5
ABC1 Class52%49%53%

Bridgnorth and The Wrekin ranks #137 for "Leave", #72 for "Right" and #46 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

Bridgnorth and The Wrekin: 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 Bridgnorth and The Wrekin 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 Bridgnorth and The Wrekin

The old seat(s) needed are:

Old seat: Ludlow

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

Old seat: LudlowTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ShropshireAlveley and Claverley3,225Bridgnorth and The Wrekin1,8184261120140002,370
ShropshireBishop's Castle2,980Ludlow and Leominster1,26533743601500002,188
ShropshireBridgnorth East and Astley Abbotts5,303Bridgnorth and The Wrekin2,5279703610380003,896
ShropshireBridgnorth West and Tasley5,460Bridgnorth and The Wrekin2,5859554200500004,010
ShropshireBroseley3,713Bridgnorth and The Wrekin1,0241,5581200240002,726
ShropshireBrown Clee3,167Ludlow and Leominster1,817406820210002,326
ShropshireChirbury and Worthen2,453Shrewsbury9504263840420001,802
ShropshireChurch Stretton and Craven Arms7,155Ludlow and Leominster3,3311,1337240670005,255
ShropshireClee3,695Ludlow and Leominster1,6655674470360002,715
ShropshireCleobury Mortimer5,775Ludlow and Leominster2,9271,1351150640004,241
ShropshireClun3,193Ludlow and Leominster1,40137939201740002,346
ShropshireCorvedale3,033Ludlow and Leominster1,9521361260130002,227
ShropshireHighley2,890Ludlow and Leominster1,1417791750270002,122
ShropshireLudlow East3,307Ludlow and Leominster97690942401210002,430
ShropshireLudlow North2,940Ludlow and Leominster1,26145633301090002,159
ShropshireLudlow South3,333Ludlow and Leominster1,4465763680570002,447
ShropshireMuch Wenlock3,446Ludlow and Leominster1,6076242680320002,531
ShropshireWorfield2,967Bridgnorth and The Wrekin1,739376490150002,179
 Total68,035 31,43212,1485,33601,05400049,970

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

Old seat: Wrekin, The

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

Old seat: Wrekin, TheTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ShropshireAlbrighton3,491Bridgnorth and The Wrekin1,683558511318500112,519
ShropshireShifnal North3,621Bridgnorth and The Wrekin1,624709351481800782,612
ShropshireShifnal South and Cosford3,956Bridgnorth and The Wrekin2,0374311042234000202,855
Telford and WrekinAdmaston and Bratton2,290Bridgnorth and The Wrekin1,0254808742100071,651
Telford and WrekinApley Castle2,444Bridgnorth and The Wrekin8565992603650071,763
Telford and WrekinArleston2,471Bridgnorth and The Wrekin6331,043138260051,782
Telford and WrekinChurch Aston and Lilleshall2,269Bridgnorth and The Wrekin1,202323811880051,637
Telford and WrekinCollege2,556Bridgnorth and The Wrekin75397044182300361,844
Telford and WrekinDonnington5,173Telford1,4341,986181868900203,733
Telford and WrekinDothill2,089Bridgnorth and The Wrekin72554314976130031,509
Telford and WrekinEdgmond and Ercall Magna4,869Bridgnorth and The Wrekin2,537729129812500113,512
Telford and WrekinErcall2,229Bridgnorth and The Wrekin953560414280031,607
Telford and WrekinHadley and Leegomery7,478Telford2,0233,164125712700145,397
Telford and WrekinHaygate2,355Bridgnorth and The Wrekin73085515582800121,698
Telford and WrekinMuxton4,943Bridgnorth and The Wrekin2,3461,12932331000173,567
Telford and WrekinNewport North and West4,615Bridgnorth and The Wrekin2,0939071351053100583,329
Telford and WrekinNewport South and East4,115Bridgnorth and The Wrekin1,85189346944100452,970
Telford and WrekinOakengates and Ketley Bank1,137Telford35140443817006820
Telford and WrekinPark2,014Bridgnorth and The Wrekin702615457840081,452
Telford and WrekinShawbirch2,426Bridgnorth and The Wrekin90056121552170051,750
Telford and WrekinWrockwardine2,101Bridgnorth and The Wrekin9934311944190091,515
 Total68,642 27,45117,8901,3451,6528040038049,522

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

New seat: Bridgnorth and The Wrekin

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

New seat: Bridgnorth and The Wrekin
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ShropshireAlbrighton3,549Wrekin, The1,683558511318500112,519
ShropshireAlveley and Claverley3,338Ludlow1,8184261120140002,370
ShropshireBridgnorth East and Astley Abbotts5,322Ludlow2,5279703610380003,896
ShropshireBridgnorth West and Tasley5,433Ludlow2,5859554200500004,010
ShropshireBroseley3,545Ludlow1,0241,5581200240002,726
ShropshireShifnal North3,533Wrekin, The1,624709351481800782,612
ShropshireShifnal South and Cosford3,645Wrekin, The2,0374311042234000202,855
ShropshireWorfield2,944Ludlow1,739376490150002,179
Telford and WrekinAdmaston and Bratton2,208Wrekin, The1,0254808742100071,651
Telford and WrekinApley Castle2,376Wrekin, The8565992603650071,763
Telford and WrekinArleston2,137Wrekin, The6331,043138260051,782
Telford and WrekinChurch Aston and Lilleshall2,381Wrekin, The1,202323811880051,637
Telford and WrekinCollege2,134Wrekin, The75397044182300361,844
Telford and WrekinDothill2,141Wrekin, The72554314976130031,509
Telford and WrekinEdgmond and Ercall Magna4,549Wrekin, The2,537729129812500113,512
Telford and WrekinErcall2,347Wrekin, The953560414280031,607
Telford and WrekinHaygate2,169Wrekin, The73085515582800121,698
Telford and WrekinMuxton4,977Wrekin, The2,3461,12932331000173,567
Telford and WrekinNewport North and West4,431Wrekin, The2,0939071351053100583,329
Telford and WrekinNewport South and East3,897Wrekin, The1,85189346944100452,970
Telford and WrekinPark2,161Wrekin, The702615457840081,452
Telford and WrekinShawbirch2,323Wrekin, The90056121552170051,750
Telford and WrekinWrockwardine2,310Wrekin, The9934311944190091,515
 Total73,850 33,33616,6212,3731,3717120034054,753

And these are the implied results for 2017 for the new seat of Bridgnorth and The Wrekin.


© 2017 Martin Baxter
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