Hertfordshire South West: New Boundaries 2018 Calculation

Hertfordshire South West: Overview

 Projection: CON seat 

Implied MP at 2017: David Gauke  (CON)
County/Area: Hertfordshire (Anglia)
Electorate: 72,404
Turnout: 75.7%

 Implied 2017 VotesImplied 2017 Share
CON33,11260.4%
LAB12,78123.3%
LIB6,55512.0%
Green1,5622.9%
UKIP7681.4%
CON Majority20,33137.1%

See overview of other seats in Anglia.

Hertfordshire South West : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Hertfordshire South West 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 WinnerCONCONCON
Economic Position11° Right8° Right
National Position2° Nat10° Nat1° Int
EU Leave %43%57%52%
British Identity47%27%29%
Good Health48%47%48%
UK Born58%89%88%
Good Education49%37%39%
Good Job64%53%51%
High SEC61%53%51%
Average Age47.149.448.5
ABC1 Class66%55%53%

Hertfordshire South West ranks #481 for "Leave", #84 for "Right" and #319 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

Hertfordshire South 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 Hertfordshire South 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 Hertfordshire South West

The old seat(s) needed are:

Old seat: Hemel Hempstead

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

Old seat: Hemel HempsteadTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
DacorumAdeyfield East3,887Hemel Hempstead1,4361,147970290002,709
DacorumAdeyfield West4,357Hemel Hempstead1,3391,3783070120003,036
DacorumApsley and Corner Hall6,457Hemel Hempstead2,4101,71923501360004,500
DacorumAshridge2,035Hertfordshire South West1,024297740240001,419
DacorumBennetts End4,829Hemel Hempstead1,6361,4542120650003,367
DacorumBoxmoor6,423Hemel Hempstead2,5361,46434501320004,477
DacorumChaulden and Warners End6,748Hemel Hempstead2,5791,7922550780004,704
DacorumGadebridge4,183Hemel Hempstead1,5601,1871290400002,916
DacorumGrovehill5,928Hemel Hempstead2,2491,6701490640004,132
DacorumHemel Hempstead Town4,231Hemel Hempstead1,3111,3852070460002,949
DacorumHighfield4,408Hemel Hempstead1,3381,3952950460003,074
DacorumKings Langley3,924Hemel Hempstead1,7477141810920002,734
DacorumLeverstock Green6,882Hemel Hempstead2,9761,4502800900004,796
DacorumNash Mills2,194Hemel Hempstead866557760310001,530
DacorumWatling4,102Hemel Hempstead1,8687681560670002,859
DacorumWoodhall Farm4,423Hemel Hempstead1,8599142370730003,083
 Total75,011 28,73419,2913,23501,02500052,285

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

Old seat: Hertfordshire South West

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

Old seat: Hertfordshire 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
DacorumAldbury and Wigginton1,846Hertfordshire South West8182852205660001,394
DacorumBerkhamsted Castle4,495Hertfordshire South West2,05455055212390003,396
DacorumBerkhamsted East4,620Hertfordshire South West1,84597446262020003,489
DacorumBerkhamsted West4,617Hertfordshire South West2,046839422111700003,488
DacorumBovingdon, Flaunden and Chipperfield6,884Hertfordshire South West3,5711,009358921710005,201
DacorumNorthchurch2,134Hertfordshire South West1,03430719714590001,611
DacorumTring Central4,016Hertfordshire South West1,750582505541420003,033
DacorumTring East2,252Hertfordshire South West1,10228325532290001,701
DacorumTring West and Rural4,030Hertfordshire South West1,642791422391520003,046
Three RiversCarpenders Park1,382Watford566324846630001,043
Three RiversChorleywood North and Sarratt5,297Hertfordshire South West3,09361521663150004,002
Three RiversChorleywood South and Maple Cross5,840Hertfordshire South West2,4091,18272225720004,410
Three RiversDickinsons4,940Hertfordshire South West1,9041,12256862750003,731
Three RiversDurrants4,637Hertfordshire South West1,7161,077546134290003,502
Three RiversMoor Park and Eastbury4,378Hertfordshire South West2,645503154140003,307
Three RiversOxhey Hall and Hayling2,817Watford992802206118110002,129
Three RiversPenn and Mill End5,395Hertfordshire South West2,0861,289477176480004,076
Three RiversRickmansworth Town5,257Hertfordshire South West2,3731,07640553650003,972
Three RiversSouth Oxhey5,457Watford1,4821,968308341220004,121
 Total80,294 35,12815,5787,0791,2931,57400060,652

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

New seat: Hertfordshire South West

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

New seat: Hertfordshire South West
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
DacorumAldbury and Wigginton1,839Hertfordshire South West8182852205660001,394
DacorumAshridge2,095Hemel Hempstead1,024297740240001,419
DacorumBerkhamsted Castle4,548Hertfordshire South West2,05455055212390003,396
DacorumBerkhamsted East4,368Hertfordshire South West1,84597446262020003,489
DacorumBerkhamsted West4,411Hertfordshire South West2,046839422111700003,488
DacorumBovingdon, Flaunden and Chipperfield6,276Hertfordshire South West3,5711,009358921710005,201
DacorumNorthchurch2,127Hertfordshire South West1,03430719714590001,611
DacorumTring Central3,822Hertfordshire South West1,750582505541420003,033
DacorumTring East2,149Hertfordshire South West1,10228325532290001,701
DacorumTring West and Rural4,017Hertfordshire South West1,642791422391520003,046
Three RiversChorleywood North and Sarratt5,848Hertfordshire South West3,09361521663150004,002
Three RiversChorleywood South and Maple Cross5,728Hertfordshire South West2,4091,18272225720004,410
Three RiversDickinsons5,147Hertfordshire South West1,9041,12256862750003,731
Three RiversDurrants5,026Hertfordshire South West1,7161,077546134290003,502
Three RiversMoor Park and Eastbury4,571Hertfordshire South West2,645503154140003,307
Three RiversPenn and Mill End5,063Hertfordshire South West2,0861,289477176480004,076
Three RiversRickmansworth Town5,369Hertfordshire South West2,3731,07640553650003,972
 Total72,404 33,11212,7816,5557681,56200054,778

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


© 2017 Martin Baxter
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