Dorset West: New Boundaries 2018 Calculation

Dorset West: Overview

 Projection: CON seat 

Implied MP at 2017: Oliver Letwin  (CON)
County/Area: Dorset (South West)
Electorate: 72,286
Turnout: 79.7%

 Implied 2017 VotesImplied 2017 Share
CON32,22756.0%
LIB13,36423.2%
LAB10,31417.9%
Green1,6882.9%
CON Majority18,86332.8%

See overview of other seats in South West.

Dorset West : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Dorset West 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 Position2° Right1° Right
National Position1° Nat1° Int
EU Leave %51%53%52%
British Identity29%27%29%
Good Health51%47%48%
UK Born92%92%88%
Good Education42%40%39%
Good Job55%50%51%
High SEC58%52%51%
Average Age49.550.548.5
ABC1 Class58%54%53%

Dorset West ranks #365 for "Leave", #281 for "Right" and #350 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

Dorset West: 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 Dorset 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.

List of old seats forming part of Dorset West

The old seat(s) needed are:

Old seat: Dorset North

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

Old seat: Dorset NorthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
East DorsetAlderholt2,532Dorset Mid1,2323531960650001,846
East DorsetCrane2,619Dorset Mid1,6391361100270001,912
East DorsetHandley Vale2,273Dorset Mid1,3861191310220001,658
East DorsetSt Leonards1,239Christchurch6951416304000903
East DorsetStour2,011Dorset Mid1,0102811540220001,467
East DorsetVerwood East4,627Christchurch2,7913222440190003,376
East DorsetVerwood West5,322Christchurch1,7831,4356440210003,883
East DorsetWest Moors and Holt1,057Christchurch52316772010000772
North DorsetAbbey3,086Dorset Mid1,67731813601200002,251
North DorsetBlackmore2,857Dorset West1,4863481810690002,084
North DorsetBlandford Central3,301Dorset Mid1,0226926020920002,408
North DorsetBlandford Hilltop1,704Dorset Mid7063711290360001,242
North DorsetBlandford Langton St Leonards1,548Dorset Mid5591803710190001,129
North DorsetBlandford Old Town1,598Dorset Mid6281303740340001,166
North DorsetBulbarrow1,551Warminster and Shaftesbury7502001060740001,130
North DorsetGillingham Rural3,298Warminster and Shaftesbury1,6222834790210002,405
North DorsetGillingham Town4,948Warminster and Shaftesbury1,9018287940860003,609
North DorsetHill Forts5,294Warminster and Shaftesbury2,67071431801610003,863
North DorsetLower Tarrants2,607Dorset Mid1,3482941750850001,902
North DorsetLydden Vale1,525Dorset West860111740680001,113
North DorsetMotcombe and Bourton3,604Warminster and Shaftesbury1,92638618101370002,630
North DorsetRiversdale and Portman3,308Dorset Mid1,4486022810820002,413
North DorsetShaftesbury East2,733Warminster and Shaftesbury1,0596173000170001,993
North DorsetShaftesbury West3,120Warminster and Shaftesbury1,05246066401010002,277
North DorsetSturminster Newton3,411Warminster and Shaftesbury1,5813604550930002,489
North DorsetThe Beacon1,799Warminster and Shaftesbury1,118105750140001,312
North DorsetThe Stours and Marnhull3,413Warminster and Shaftesbury1,69644024601080002,490
 Total76,385 36,16810,3937,55501,60700055,723

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

Old seat: Dorset South

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

Old seat: Dorset SouthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
PurbeckCastle1,391Dorset South63730732022000998
PurbeckCreech Barrow1,397Dorset South707249160310001,003
PurbeckLangton1,192Dorset South58416123086000854
PurbeckLulworth and Winfrith1,389Dorset South69324247015000997
PurbeckSwanage North3,584Dorset South1,67160818201110002,572
PurbeckSwanage South3,974Dorset South1,58880823802170002,851
PurbeckWool5,208Dorset South2,40183937501240003,739
West DorsetBroadmayne and Crossways2,811Dorset South1,2704062670740002,017
West DorsetPuddletown195Dorset West91281307000139
Weymouth and PortlandLittlemoor2,917Dorset South7691,237500380002,094
Weymouth and PortlandMelcombe Regis4,630Dorset South1,7121,22320101880003,324
Weymouth and PortlandPreston3,821Dorset South1,8696122270350002,743
Weymouth and PortlandRadipole2,943Dorset South1,1147442100450002,113
Weymouth and PortlandTophill East2,888Dorset South1,0958462901030002,073
Weymouth and PortlandTophill West4,068Dorset South1,5841,181660870002,918
Weymouth and PortlandUnderhill3,146Dorset South1,504636530650002,258
Weymouth and PortlandUpwey and Broadwey2,826Dorset South1,1007454401390002,028
Weymouth and PortlandWestham East3,024Dorset South8721,0012380600002,171
Weymouth and PortlandWestham North4,090Dorset South1,3331,1883430710002,935
Weymouth and PortlandWestham West2,826Dorset South9228821830410002,028
Weymouth and PortlandWey Valley2,686Dorset South1,2475323001200001,929
Weymouth and PortlandWeymouth East2,856Dorset South1,1405998202280002,049
Weymouth and PortlandWeymouth West4,062Dorset South1,5531,0655602410002,915
Weymouth and PortlandWyke Regis4,400Dorset South1,6791,3024701290003,157
 Total72,324 29,13517,4413,05202,27700051,905

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

Old seat: Dorset West

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

Old seat: Dorset WestTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
West DorsetBeaminster4,298Dorset West1,9083459110770003,241
West DorsetBridport North6,237Dorset West2,2951,0041,26601380004,703
West DorsetBridport South5,371Dorset West1,8979761,01801570004,048
West DorsetBroadmayne and Crossways1,309Dorset South566151258012000987
West DorsetBroadwindsor2,112Dorset West1,0981922520500001,592
West DorsetBurton Bradstock2,132Dorset West9632223470750001,607
West DorsetCerne Valley4,126Dorset West1,8515496480620003,110
West DorsetChickerell and Chesil Bank5,772Dorset South2,7269186360720004,352
West DorsetChideock and Symondsbury1,998Dorset West9451803230590001,507
West DorsetDorchester East4,094Dorset West1,1038141,0770920003,086
West DorsetDorchester North4,469Dorset West1,38298189301140003,370
West DorsetDorchester South3,452Dorset West9577128730600002,602
West DorsetDorchester West3,757Dorset West1,1847258520710002,832
West DorsetFrome Valley1,920Dorset West1,0721671550540001,448
West DorsetLyme Regis and Charmouth4,121Dorset West1,9333317450990003,108
West DorsetMaiden Newton2,183Dorset West1,0553781480650001,646
West DorsetNetherbury2,070Dorset West9921693280720001,561
West DorsetPiddle Valley2,126Dorset West1,0882691960480001,601
West DorsetPuddletown1,816Dorset West8452212750280001,369
West DorsetQueen Thorne2,004Dorset West1,1162361240360001,512
West DorsetSherborne East3,966Dorset West1,8444396080990002,990
West DorsetSherborne West3,914Dorset West1,5963301,0060200002,952
West DorsetWinterborne St Martin1,983Dorset West9103531850480001,496
West DorsetYetminster and Cam Vale3,814Dorset West1,7562348660200002,876
 Total79,044 33,08210,89613,99001,62800059,596

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

New seat: Dorset West

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

New seat: Dorset West
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
North DorsetBlackmore2,777Dorset North1,4863481810690002,084
North DorsetLydden Vale1,464Dorset North860111740680001,113
West DorsetBeaminster4,101Dorset West1,9083459110770003,241
West DorsetBridport North5,784Dorset West2,2951,0041,26601380004,703
West DorsetBridport South5,133Dorset West1,8979761,01801570004,048
West DorsetBroadwindsor2,093Dorset West1,0981922520500001,592
West DorsetBurton Bradstock2,084Dorset West9632223470750001,607
West DorsetCerne Valley4,043Dorset West1,8515496480620003,110
West DorsetChideock and Symondsbury1,933Dorset West9451803230590001,507
West DorsetDorchester East3,614Dorset West1,1038141,0770920003,086
West DorsetDorchester North4,206Dorset West1,38298189301140003,370
West DorsetDorchester South3,430Dorset West9577128730600002,602
West DorsetDorchester West3,539Dorset West1,1847258520710002,832
West DorsetFrome Valley1,865Dorset West1,0721671550540001,448
West DorsetLyme Regis and Charmouth3,920Dorset West1,9333317450990003,108
West DorsetMaiden Newton2,024Dorset West1,0553781480650001,646
West DorsetNetherbury2,029Dorset West9921693280720001,561
West DorsetPiddle Valley2,060Dorset West1,0882691960480001,601
West DorsetPuddletown189Dorset South91242803000146
West DorsetPuddletown1,765Dorset West8452252600320001,362
West DorsetQueen Thorne1,911Dorset West1,1162361240360001,512
West DorsetSherborne East3,693Dorset West1,8444396080990002,990
West DorsetSherborne West3,067Dorset West1,5963301,0060200002,952
West DorsetWinterborne St Martin1,874Dorset West9103531850480001,496
West DorsetYetminster and Cam Vale3,688Dorset West1,7562348660200002,876
 Total72,286 32,22710,31413,36401,68800057,593

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


© 2017 Martin Baxter
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