Plymouth Sutton and Devonport: New Boundaries 2018 Calculation

Plymouth Sutton and Devonport: Overview

 Projection: LAB seat 

Implied MP at 2017: Luke Pollard  (LAB)
County/Area: Devon (South West)
Electorate: 78,406
Turnout: 68.7%

 Implied 2017 VotesImplied 2017 Share
LAB26,32048.9%
CON23,68844.0%
UKIP1,7443.2%
LIB1,2962.4%
Green6161.1%
OTH1910.4%
LAB Majority2,6324.9%

See overview of other seats in South West.

Plymouth Sutton and Devonport : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Plymouth Sutton and Devonport 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 WinnerLABCONCON
Economic Position1° Left1° Right
National Position3° Nat1° Nat1° Int
EU Leave %55%53%52%
British Identity42%27%29%
Good Health51%47%48%
UK Born67%92%88%
Good Education53%40%39%
Good Job64%50%51%
High SEC57%52%51%
Average Age43.050.548.5
ABC1 Class64%54%53%

Plymouth Sutton and Devonport ranks #253 for "Leave", #362 for "Right" and #280 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

Plymouth Sutton and Devonport: 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 Plymouth Sutton and Devonport 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 Plymouth Sutton and Devonport

The old seat(s) needed are:

Old seat: Devon South West

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

Old seat: Devon South WestTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
PlymouthPlympton Chaddlewood6,576Plympton, Tavistock and Ivybridge2,4692,002129227500004,877
PlymouthPlympton Erle7,100Plympton, Tavistock and Ivybridge2,6112,115272210590005,267
PlymouthPlympton St Mary10,319Plympton, Tavistock and Ivybridge4,7172,398178264960007,653
PlymouthPlymstock Dunstone9,855Plymouth Sutton and Devonport4,3552,259287336720007,309
PlymouthPlymstock Radford10,025Plymouth Sutton and Devonport4,2142,742103331460007,436
South HamsBickleigh and Cornwood2,210Plympton, Tavistock and Ivybridge1,10332812720620001,640
South HamsCharterlands2,199Plympton, Tavistock and Ivybridge1,130353707710001,631
South HamsErmington and Ugborough2,089Plympton, Tavistock and Ivybridge1,0082841685850001,550
South HamsIvybridge East4,597Plympton, Tavistock and Ivybridge1,93886045958940003,409
South HamsIvybridge West4,960Plympton, Tavistock and Ivybridge2,566797109391670003,678
South HamsLoddiswell and Aveton Gifford720Totnes3749133234000534
South HamsNewton and Yealmpton4,592Plympton, Tavistock and Ivybridge2,14158453381400003,406
South HamsWembury and Brixton3,568Plympton, Tavistock and Ivybridge1,8095532076710002,646
South HamsWoolwell2,453Plympton, Tavistock and Ivybridge1,1984515726870001,819
 Total71,263 31,63315,8172,7321,5391,13400052,855

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

Old seat: Plymouth Sutton and Devonport

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

Old seat: Plymouth Sutton and DevonportTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
PlymouthCompton8,735Plymouth Sutton and Devonport2,5552,225169952800185,090
PlymouthDevonport10,132Plymouth Sutton and Devonport2,0403,479692682300235,902
PlymouthDrake7,796Plymouth Sutton and Devonport1,6992,4621673217000134,543
PlymouthEfford and Lipson9,832Plymouth Sutton and Devonport1,9013,440882403200285,729
PlymouthPeverell9,464Plymouth Moor View2,6882,489201704200235,513
PlymouthSt Peter and the Waterfront10,988Plymouth Sutton and Devonport2,4373,50912116710800616,403
PlymouthStoke9,637Plymouth Sutton and Devonport2,3732,917961604700225,615
PlymouthSutton and Mount Gould10,000Plymouth Sutton and Devonport2,1143,2871961159000265,828
 Total76,584 17,80723,8081,1071,1475400021444,623

The full details of these calculations are given on the Plymouth Sutton and Devonport seat details page. Click on "Show workings".

New seat: Plymouth Sutton and Devonport

The new seat of Plymouth Sutton and Devonport is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Plymouth Sutton and Devonport
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
PlymouthCompton8,529Plymouth Sutton and Devonport2,5552,225169952800185,090
PlymouthDevonport9,380Plymouth Sutton and Devonport2,0403,479692682300235,902
PlymouthDrake5,504Plymouth Sutton and Devonport1,6992,4621673217000134,543
PlymouthEfford and Lipson9,121Plymouth Sutton and Devonport1,9013,440882403200285,729
PlymouthPlymstock Dunstone9,465Devon South West4,3552,259287336720007,309
PlymouthPlymstock Radford9,800Devon South West4,2142,742103331460007,436
PlymouthSt Peter and the Waterfront9,221Plymouth Sutton and Devonport2,4373,50912116710800616,403
PlymouthStoke8,796Plymouth Sutton and Devonport2,3732,917961604700225,615
PlymouthSutton and Mount Gould8,590Plymouth Sutton and Devonport2,1143,2871961159000265,828
 Total78,406 23,68826,3201,2961,7446160019153,855

And these are the implied results for 2017 for the new seat of Plymouth Sutton and Devonport.


© 2017 Martin Baxter
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