Bath: New Boundaries 2018 Calculation

Bath: Overview

 Projection: LIB seat 

Implied MP at 2017: Wera Hobhouse  (LIB)
County/Area: Bristol area (South West)
Electorate: 73,586
Turnout: 81.4%

 Implied 2017 VotesImplied 2017 Share
LIB24,64341.1%
CON22,85938.2%
LAB10,83518.1%
Green1,3962.3%
OTH1780.3%
LIB Majority1,7843.0%

See overview of other seats in South West.

Bath : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Bath 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 WinnerLIBCONCON
Economic Position3° Left1° Right
National Position13° Int1° Nat1° Int
EU Leave %35%53%52%
British Identity33%27%29%
Good Health52%47%48%
UK Born87%92%88%
Good Education57%40%39%
Good Job61%50%51%
High SEC57%52%51%
Average Age46.250.548.5
ABC1 Class68%54%53%

Bath ranks #555 for "Leave", #393 for "Right" and #482 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

Bath: 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 Bath 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 Bath

The old seat(s) needed are:

Old seat: Bath

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

Old seat: BathTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Bath and North East SomersetAbbey4,245Bath1,2793881,3860990003,152
Bath and North East SomersetBathwick3,649Bath1,3142651,0860440002,709
Bath and North East SomersetCombe Down4,077Bath1,1923631,4380350003,028
Bath and North East SomersetKingsmead4,111Bath1,0744021,44801300003,054
Bath and North East SomersetLambridge4,097Bath1,0294871,4510750003,042
Bath and North East SomersetLansdown3,472Bath1,3021761,0160840002,578
Bath and North East SomersetLyncombe4,101Bath1,2073321,4370690003,045
Bath and North East SomersetNewbridge4,461Bath1,2914131,5620470003,313
Bath and North East SomersetOdd Down4,269Bath9825251,6230400003,170
Bath and North East SomersetOldfield4,371Bath9486831,5410740003,246
Bath and North East SomersetSouthdown4,170Bath1,0015151,5500310003,097
Bath and North East SomersetTwerton4,006Bath6967961,4540290002,975
Bath and North East SomersetWalcot4,447Bath1,0045481,62601240003,302
Bath and North East SomersetWestmoreland4,894Bath9966881,83701130003,634
Bath and North East SomersetWeston4,028Bath1,2083801,3790250002,992
Bath and North East SomersetWidcombe4,369Bath1,2193191,60101050003,244
 Total66,767 17,7427,28023,43501,12400049,581

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

Old seat: Somerset North East

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

Old seat: Somerset North EastTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Bath and North East SomersetBathavon North5,856Bath2,4121,281592012500264,436
Bath and North East SomersetBathavon South2,493Bath98148132109300131,889
Bath and North East SomersetBathavon West1,919Somerset North East86835613707700161,454
Bath and North East SomersetChew Valley North1,960Somerset North East9972831310660081,485
Bath and North East SomersetChew Valley South1,940Somerset North East1,0183147804700121,469
Bath and North East SomersetClutton2,104Somerset North East8984661920280091,593
Bath and North East SomersetFarmborough2,030Somerset North East1,1032841300120081,537
Bath and North East SomersetHigh Littleton2,470Somerset North East1,2364171360740091,872
Bath and North East SomersetKeynsham East4,430Somerset North East2,00393335804600163,356
Bath and North East SomersetKeynsham North4,226Somerset North East1,7121,27113706500153,200
Bath and North East SomersetKeynsham South4,166Somerset North East1,6201,29718504000143,156
Bath and North East SomersetMendip2,202Somerset North East1,10837111705800131,667
Bath and North East SomersetMidsomer Norton North4,797Somerset North East1,9721,32223307900283,634
Bath and North East SomersetMidsomer Norton Redfield4,198Somerset North East1,8971,05415106000193,181
Bath and North East SomersetPaulton4,366Somerset North East1,3181,67722504000463,306
Bath and North East SomersetPeasedown5,290Bath1,7241,793295054001394,005
Bath and North East SomersetPublow and Whitchurch2,017Somerset North East1,062326850460081,527
Bath and North East SomersetRadstock4,597Somerset North East1,3961,58934809000583,481
Bath and North East SomersetSaltford3,339Somerset North East1,50166829804900152,531
Bath and North East SomersetTimsbury2,151Somerset North East7436769804600661,629
Bath and North East SomersetWestfield4,800Somerset North East1,4221,89821405000513,635
 Total71,351 28,99118,7574,46101,2450058954,043

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

New seat: Bath

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

New seat: Bath
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Bath and North East SomersetAbbey3,554Bath1,2793881,3860990003,152
Bath and North East SomersetBathavon North5,586Somerset North East2,4121,281592012500264,436
Bath and North East SomersetBathavon South2,105Somerset North East98148132109300131,889
Bath and North East SomersetBathwick3,262Bath1,3142651,0860440002,709
Bath and North East SomersetCombe Down3,813Bath1,1923631,4380350003,028
Bath and North East SomersetKingsmead3,526Bath1,0744021,44801300003,054
Bath and North East SomersetLambridge4,062Bath1,0294871,4510750003,042
Bath and North East SomersetLansdown3,097Bath1,3021761,0160840002,578
Bath and North East SomersetLyncombe4,175Bath1,2073321,4370690003,045
Bath and North East SomersetNewbridge4,119Bath1,2914131,5620470003,313
Bath and North East SomersetOdd Down3,912Bath9825251,6230400003,170
Bath and North East SomersetOldfield3,919Bath9486831,5410740003,246
Bath and North East SomersetPeasedown4,929Somerset North East1,7241,793295054001394,005
Bath and North East SomersetSouthdown4,005Bath1,0015151,5500310003,097
Bath and North East SomersetTwerton3,578Bath6967961,4540290002,975
Bath and North East SomersetWalcot4,004Bath1,0045481,62601240003,302
Bath and North East SomersetWestmoreland4,424Bath9966881,83701130003,634
Bath and North East SomersetWeston3,989Bath1,2083801,3790250002,992
Bath and North East SomersetWidcombe3,527Bath1,2193191,60101050003,244
 Total73,586 22,85910,83524,64301,3960017859,911

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


© 2017 Martin Baxter
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