Chesham and Amersham: New Boundaries 2018 Calculation

Chesham and Amersham: Overview

 Projection: CON seat 

Implied MP at 2017: Cheryl Gillan  (CON)
County/Area: Buckinghamshire (South East)
Electorate: 77,089
Turnout: 79.6%

 Implied 2017 VotesImplied 2017 Share
CON38,09062.1%
LAB12,20719.9%
LIB7,61612.4%
Green1,8553.0%
UKIP1,5432.5%
OTH350.1%
CON Majority25,88342.2%

See overview of other seats in South East.

Chesham and Amersham : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Chesham and Amersham constituency, the 'South East' 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 EastAll GB
Party WinnerCONCONCON
Economic Position12° Right4° Right
National Position4° Nat3° Nat1° Int
EU Leave %45%52%52%
British Identity28%29%29%
Good Health48%49%48%
UK Born93%88%88%
Good Education38%43%39%
Good Job54%56%51%
High SEC54%57%51%
Average Age50.349.248.5
ABC1 Class56%60%53%

Chesham and Amersham ranks #457 for "Leave", #67 for "Right" and #260 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

Chesham and Amersham: 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 Chesham and Amersham 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 Chesham and Amersham

The old seat(s) needed are:

Old seat: Aylesbury

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

Old seat: AylesburyTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Aylesbury ValeAston Clinton and Stoke Mandeville7,385Aylesbury3,4531,3012529710800445,255
Aylesbury ValeBedgrove4,804Aylesbury1,9958482926446001733,418
Aylesbury ValeCentral and Walton4,856Aylesbury1,6701,223363818600333,456
Aylesbury ValeColdharbour7,143Aylesbury2,4111,6867557610900485,085
Aylesbury ValeElmhurst5,218Aylesbury1,5211,6173981035100243,714
Aylesbury ValeGatehouse5,341Aylesbury1,6291,4594771397000283,802
Aylesbury ValeMandeville and Elm Farm6,670Aylesbury2,5201,5294591208200374,747
Aylesbury ValeOakfield and Bierton4,507Aylesbury1,621992442715600263,208
Aylesbury ValeRiverside3,590Aylesbury1,1399882661221300272,555
Aylesbury ValeSouthcourt4,959Aylesbury1,2471,5914841274600343,529
Aylesbury ValeWalton Court and Hawkslade4,877Aylesbury1,5671,3344111032600303,471
Aylesbury ValeWatermead1,793Aylesbury760318158161300101,275
Aylesbury ValeWendover and Halton6,330Aylesbury2,8071,1033257015900404,504
WycombeBledlow and Bradenham2,295Wycombe1,315204351690091,633
WycombeGreater Hughenden6,398Chesham and Amersham3,3846083971811800284,553
WycombeLacey Green, Speen and the Hampdens2,159Chesham and Amersham1,192223400740071,536
WycombeStokenchurch and Radnage4,220Wycombe2,0815931078811000233,002
 Total82,545 32,31217,6175,6611,2961,2360062158,743

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

Old seat: Chesham and Amersham

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

Old seat: Chesham and AmershamTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ChilternAmersham Common2,017Chesham and Amersham83833431240350001,559
ChilternAmersham Town3,644Chesham and Amersham1,48861456959860002,816
ChilternAmersham-on-the-Hill3,826Chesham and Amersham1,80353854714560002,958
ChilternAsheridge Vale and Lowndes3,707Chesham and Amersham1,29770973048820002,866
ChilternAshley Green, Latimer and Chenies1,688Chesham and Amersham89415322319170001,306
ChilternAustenwood1,696Chesham and Amersham87017920824300001,311
ChilternBallinger, South Heath and Chartridge1,721Chesham and Amersham68121629744930001,331
ChilternCentral3,374Chesham and Amersham1,709525170142630002,609
ChilternChalfont Common3,039Chesham and Amersham1,61533529568370002,350
ChilternChalfont St Giles5,515Chesham and Amersham3,048632379111930004,263
ChilternChesham Bois and Weedon Hill4,000Chesham and Amersham2,14250234537680003,094
ChilternCholesbury, The Lee and Bellingdon1,774Chesham and Amersham85624816566380001,373
ChilternGold Hill1,691Chesham and Amersham70737012775280001,307
ChilternGreat Missenden1,801Chesham and Amersham687540784830001,392
ChilternHilltop and Townsend3,531Chesham and Amersham1,2767424361031740002,731
ChilternHolmer Green3,098Chesham and Amersham1,82531015290180002,395
ChilternLittle Chalfont3,687Chesham and Amersham1,80649440189600002,850
ChilternLittle Missenden1,923Chesham and Amersham8744668810500001,488
ChilternNewtown1,921Chesham and Amersham724492129291120001,486
ChilternPenn and Coleshill3,504Chesham and Amersham2,36016514319220002,709
ChilternPrestwood and Heath End5,118Chesham and Amersham2,701639394155670003,956
ChilternRidgeway2,011Chesham and Amersham52168019293690001,555
ChilternSeer Green1,789Chesham and Amersham86432012045350001,384
ChilternSt Mary's and Waterside3,759Chesham and Amersham1,3568024331072090002,907
ChilternVale1,631Chesham and Amersham57237124634380001,261
 Total71,465 33,51411,3767,1791,5251,66300055,257

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

New seat: Chesham and Amersham

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

New seat: Chesham and Amersham
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ChilternAmersham Common1,865Chesham and Amersham83833431240350001,559
ChilternAmersham Town3,339Chesham and Amersham1,48861456959860002,816
ChilternAmersham-on-the-Hill3,520Chesham and Amersham1,80353854714560002,958
ChilternAsheridge Vale and Lowndes3,580Chesham and Amersham1,29770973048820002,866
ChilternAshley Green, Latimer and Chenies1,725Chesham and Amersham89415322319170001,306
ChilternAustenwood1,646Chesham and Amersham87017920824300001,311
ChilternBallinger, South Heath and Chartridge1,703Chesham and Amersham68121629744930001,331
ChilternCentral3,091Chesham and Amersham1,709525170142630002,609
ChilternChalfont Common3,075Chesham and Amersham1,61533529568370002,350
ChilternChalfont St Giles5,202Chesham and Amersham3,048632379111930004,263
ChilternChesham Bois and Weedon Hill3,831Chesham and Amersham2,14250234537680003,094
ChilternCholesbury, The Lee and Bellingdon1,837Chesham and Amersham85624816566380001,373
ChilternGold Hill1,582Chesham and Amersham70737012775280001,307
ChilternGreat Missenden1,693Chesham and Amersham687540784830001,392
ChilternHilltop and Townsend3,330Chesham and Amersham1,2767424361031740002,731
ChilternHolmer Green3,279Chesham and Amersham1,82531015290180002,395
ChilternLittle Chalfont3,815Chesham and Amersham1,80649440189600002,850
ChilternLittle Missenden1,869Chesham and Amersham8744668810500001,488
ChilternNewtown1,701Chesham and Amersham724492129291120001,486
ChilternPenn and Coleshill3,450Chesham and Amersham2,36016514319220002,709
ChilternPrestwood and Heath End5,029Chesham and Amersham2,701639394155670003,956
ChilternRidgeway1,782Chesham and Amersham52168019293690001,555
ChilternSeer Green1,721Chesham and Amersham86432012045350001,384
ChilternSt Mary's and Waterside3,444Chesham and Amersham1,3568024331072090002,907
ChilternVale1,451Chesham and Amersham57237124634380001,261
WycombeGreater Hughenden6,486Aylesbury3,3846083971811800284,553
WycombeLacey Green, Speen and the Hampdens2,043Aylesbury1,192223400740071,536
 Total77,089 38,09012,2077,6161,5431,855003561,346

And these are the implied results for 2017 for the new seat of Chesham and Amersham.


© 2017 Martin Baxter
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