Dorset South: New Boundaries 2018 Calculation

Dorset South: Overview

 Projection: CON seat 

Implied MP at 2017: Richard Drax  (CON)
County/Area: Dorset (South West)
Electorate: 74,789
Turnout: 76.4%

 Implied 2017 VotesImplied 2017 Share
CON Majority13,85424.3%

See overview of other seats in South West.

Dorset South : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Dorset South 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
Economic Position1° Right1° Right
National Position5° Nat1° Nat1° Int
EU Leave %59%53%52%
British Identity27%27%29%
Good Health43%47%48%
UK Born95%92%88%
Good Education37%40%39%
Good Job48%50%51%
High SEC51%52%51%
Average Age52.350.548.5
ABC1 Class50%54%53%

Dorset South ranks #160 for "Leave", #307 for "Right" and #235 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:

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 South: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015


This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Dorset South 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 South

The old seat(s) needed are:

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
New SeatCON
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
New SeatCON
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 South

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

New seat: Dorset South
Old Seat CON
PurbeckCastle1,411Dorset South63730732022000998
PurbeckCreech Barrow1,475Dorset South707249160310001,003
PurbeckLangton1,281Dorset South58416123086000854
PurbeckLulworth and Winfrith1,331Dorset South69324247015000997
PurbeckSwanage North3,734Dorset South1,67160818201110002,572
PurbeckSwanage South3,862Dorset South1,58880823802170002,851
PurbeckWool4,503Dorset South2,40183937501240003,739
West DorsetBroadmayne and Crossways2,866Dorset South1,2533803580590002,050
West DorsetBroadmayne and Crossways1,335Dorset West583177167027000954
West DorsetChickerell and Chesil Bank5,466Dorset West2,7269186360720004,352
Weymouth and PortlandLittlemoor2,442Dorset South7691,237500380002,094
Weymouth and PortlandMelcombe Regis3,979Dorset South1,7121,22320101880003,324
Weymouth and PortlandPreston4,213Dorset South1,8696122270350002,743
Weymouth and PortlandRadipole2,787Dorset South1,1147442100450002,113
Weymouth and PortlandTophill East2,477Dorset South1,0958462901030002,073
Weymouth and PortlandTophill West3,689Dorset South1,5841,181660870002,918
Weymouth and PortlandUnderhill2,573Dorset South1,504636530650002,258
Weymouth and PortlandUpwey and Broadwey2,780Dorset South1,1007454401390002,028
Weymouth and PortlandWestham East2,610Dorset South8721,0012380600002,171
Weymouth and PortlandWestham North4,003Dorset South1,3331,1883430710002,935
Weymouth and PortlandWestham West2,752Dorset South9228821830410002,028
Weymouth and PortlandWey Valley2,760Dorset South1,2475323001200001,929
Weymouth and PortlandWeymouth East2,493Dorset South1,1405998202280002,049
Weymouth and PortlandWeymouth West3,848Dorset South1,5531,0655602410002,915
Weymouth and PortlandWyke Regis4,119Dorset South1,6791,3024701290003,157
 Total74,789 32,33618,4823,93302,35400057,105

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

© 2018 Electoral Calculus Ltd
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