Cambridge: New Boundaries 2018 Calculation

Cambridge: Overview

 Projection: LAB seat 

Implied MP at 2017: Daniel Zeichner  (LAB)
County/Area: Cambridgeshire (Anglia)
Electorate: 72,757
Turnout: 84.3%

 Implied 2017 VotesImplied 2017 Share
LAB31,08150.7%
LIB17,77729.0%
CON10,89717.8%
Green1,4292.3%
OTH1340.2%
LAB Majority13,30421.7%

See overview of other seats in Anglia.

Cambridge : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Cambridge constituency, the 'Anglia' 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.

IndicatorSeatAngliaAll GB
Party WinnerLABCONCON
Economic Position10° Left8° Right
National Position19° Int10° Nat1° Int
EU Leave %26%57%52%
British Identity27%27%29%
Good Health47%47%48%
UK Born92%89%88%
Good Education38%37%39%
Good Job51%53%51%
High SEC52%53%51%
Average Age48.749.448.5
ABC1 Class52%55%53%

Cambridge ranks #582 for "Leave", #488 for "Right" and #531 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

Cambridge: 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 Cambridge 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 Cambridge

The old seat(s) needed are:

Old seat: Cambridge

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

Old seat: CambridgeTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
CambridgeAbbey6,718Cambridge8392,7001,18608400104,819
CambridgeArbury6,248Cambridge5722,5011,31008100164,480
CambridgeCastle6,655Cambridge9682,1881,46501430074,771
CambridgeCherry Hinton6,062Cambridge8832,4071,0230270064,346
CambridgeColeridge6,392Cambridge7772,4821,2590620044,584
CambridgeEast Chesterton6,362Cambridge7122,4681,3290500034,562
CambridgeKing's Hedges6,181Cambridge7142,5191,08605000634,432
CambridgeMarket4,862Cambridge6781,5821,05001740023,486
CambridgeNewnham5,361Cambridge7101,8051,2370840073,843
CambridgePetersfield5,653Cambridge3512,3381,19501670044,055
CambridgeRomsey6,272Cambridge4282,4721,42601630084,497
CambridgeTrumpington5,465Cambridge9341,7121,2210510023,920
CambridgeWest Chesterton5,772Cambridge5671,8581,58501280024,140
 Total78,003 9,13329,03216,37201,2640013455,935

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

Old seat: Cambridgeshire South

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

Old seat: Cambridgeshire SouthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
CambridgeQueen Edith's7,069Cambridge1,7642,0491,40501650005,383
South CambridgeshireBar Hill3,921Cambridgeshire South1,6628114460670002,986
South CambridgeshireBarton1,949Cambridgeshire South8703841690610001,484
South CambridgeshireBassingbourn3,944Letchworth and Royston1,80876528401470003,004
South CambridgeshireBourn8,019Cambridgeshire South3,3192,07753401770006,107
South CambridgeshireCaldecote1,896Cambridgeshire South636247552090001,444
South CambridgeshireComberton1,834Cambridgeshire South8133122450260001,396
South CambridgeshireCottenham6,262Cambridgeshire South2,5841,25977801490004,770
South CambridgeshireDuxford2,176Cambridgeshire South9744012510310001,657
South CambridgeshireFowlmere and Foxton1,880Cambridgeshire South8244301410360001,431
South CambridgeshireGamlingay3,823Cambridgeshire South1,4614849450210002,911
South CambridgeshireGirton3,536Cambridgeshire South1,31080846201120002,692
South CambridgeshireHardwick2,085Cambridgeshire South8483803400190001,587
South CambridgeshireHarston and Hauxton1,874Cambridgeshire South6423004690150001,426
South CambridgeshireHaslingfield and The Eversdens2,061Cambridgeshire South5924624790360001,569
South CambridgeshireLongstanton2,067Cambridgeshire South1,052334179090001,574
South CambridgeshireMelbourn4,366Letchworth and Royston1,4087211,1750210003,325
South CambridgeshireMeldreth1,972Letchworth and Royston6023065590340001,501
South CambridgeshireOrwell and Barrington1,811Cambridgeshire South7072713810200001,379
South CambridgeshirePapworth and Elsworth3,799Cambridgeshire South1,6768013630530002,893
South CambridgeshireSawston5,569Cambridgeshire South2,3771,40535901000004,241
South CambridgeshireSwavesey1,913Cambridgeshire South9073132050330001,458
South CambridgeshireThe Abingtons1,777Cambridgeshire South851389112010001,353
South CambridgeshireThe Mordens1,873Letchworth and Royston8144771240110001,426
South CambridgeshireThe Shelfords and Stapleford5,681Cambridgeshire South2,1481,16986501450004,327
South CambridgeshireWhittlesford2,101Cambridgeshire South9823232820130001,600
 Total85,258 33,63117,67812,10401,51100064,924

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

New seat: Cambridge

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

New seat: Cambridge
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
CambridgeAbbey5,522Cambridge8392,7001,18608400104,819
CambridgeArbury5,338Cambridge5722,5011,31008100164,480
CambridgeCastle5,086Cambridge9682,1881,46501430074,771
CambridgeCherry Hinton5,449Cambridge8832,4071,0230270064,346
CambridgeColeridge5,280Cambridge7772,4821,2590620044,584
CambridgeEast Chesterton5,459Cambridge7122,4681,3290500034,562
CambridgeKing's Hedges5,075Cambridge7142,5191,08605000634,432
CambridgeMarket4,528Cambridge6781,5821,05001740023,486
CambridgeNewnham4,596Cambridge7101,8051,2370840073,843
CambridgePetersfield4,275Cambridge3512,3381,19501670044,055
CambridgeQueen Edith's5,491Cambridgeshire South1,7642,0491,40501650005,383
CambridgeRomsey5,210Cambridge4282,4721,42601630084,497
CambridgeTrumpington6,347Cambridge9341,7121,2210510023,920
CambridgeWest Chesterton5,101Cambridge5671,8581,58501280024,140
 Total72,757 10,89731,08117,77701,4290013461,318

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


© 2017 Martin Baxter
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