Bath: New Boundaries 2018 Calculation

Bath: Overview

Projection: LIB seat

Implied MP at 2017:Wera Hobhouse  (LIB)
County/Area:Bristol area (South West)
Electorate:80,406
Turnout:74.5%

PartyImplied 2017 VotesImplied 2017 Share
LIB24,52140.9%
CON23,12738.6%
LAB10,76018.0%
Green1,3892.3%
OTH1150.2%
LIB Majority1,3942.3%

See overview of other seats in South West.



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.

Bath: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015, Map © OpenStreetMap contributors

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 SomersetAbbey3,554Bath1,2114991,3660770003,153
Bath and North East SomersetBathwick3,262Bath1,1383101,2060550002,709
Bath and North East SomersetCombe Down3,813Bath1,1553651,4460620003,028
Bath and North East SomersetKingsmead3,526Bath1,0764451,4550770003,053
Bath and North East SomersetLambridge4,062Bath1,0794921,3950760003,042
Bath and North East SomersetLansdown3,097Bath1,2722271,0200600002,579
Bath and North East SomersetLyncombe4,175Bath1,3122411,4230690003,045
Bath and North East SomersetNewbridge4,119Bath1,3213841,5400690003,314
Bath and North East SomersetOdd Down3,912Bath1,0324321,6460610003,171
Bath and North East SomersetOldfield3,919Bath9456801,5530670003,245
Bath and North East SomersetSouthdown4,005Bath9494551,6320600003,096
Bath and North East SomersetTwerton3,578Bath6277681,5220580002,975
Bath and North East SomersetWalcot4,004Bath9436411,6300890003,303
Bath and North East SomersetWestmoreland4,424Bath1,0936371,80001040003,634
Bath and North East SomersetWeston3,989Bath1,3603141,2540630002,991
Bath and North East SomersetWidcombe3,527Bath1,2313881,5470780003,244
 Total60,966 17,7447,27823,43501,12500049,582

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 North5,586Bath2,4741,290518012100324,435
Bath and North East SomersetBathavon South2,105Bath1,0395552310540091,888
Bath and North East SomersetBathavon West1,984Somerset North East79544015003800311,454
Bath and North East SomersetChew Valley North1,923Somerset North East95237311503100121,483
Bath and North East SomersetChew Valley South2,037Somerset North East977369860300071,469
Bath and North East SomersetClutton1,993Somerset North East9304631560360091,594
Bath and North East SomersetFarmborough2,034Somerset North East1,0213731200170071,538
Bath and North East SomersetHigh Littleton2,358Somerset North East1,16951213903900121,871
Bath and North East SomersetKeynsham East4,412Somerset North East1,93198333307900293,355
Bath and North East SomersetKeynsham North4,001Somerset North East1,7351,17119708000183,201
Bath and North East SomersetKeynsham South4,034Somerset North East1,5701,25723907100193,156
Bath and North East SomersetMendip2,111Somerset North East1,0684441130360081,669
Bath and North East SomersetMidsomer Norton North4,468Somerset North East1,9041,36721808200623,633
Bath and North East SomersetMidsomer Norton Redfield4,170Somerset North East1,8701,00920607100233,179
Bath and North East SomersetPaulton4,332Somerset North East1,4591,54618206500543,306
Bath and North East SomersetPeasedown4,929Bath1,8701,63733708900744,007
Bath and North East SomersetPublow and Whitchurch2,018Somerset North East9754141000310071,527
Bath and North East SomersetRadstock3,928Somerset North East1,4001,55038108800623,481
Bath and North East SomersetSaltford3,419Somerset North East1,51568026106000132,529
Bath and North East SomersetTimsbury2,067Somerset North East83458312604700391,629
Bath and North East SomersetWestfield4,532Somerset North East1,5051,74125207900603,637
 Total68,441 28,99318,7574,46001,2440058754,041

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 SomersetAbbey4,245Bath1,2114991,3660770003,153
Bath and North East SomersetBathavon North5,856Somerset North East2,4741,290518012100324,435
Bath and North East SomersetBathavon South2,493Somerset North East1,0395552310540091,888
Bath and North East SomersetBathwick3,649Bath1,1383101,2060550002,709
Bath and North East SomersetCombe Down4,077Bath1,1553651,4460620003,028
Bath and North East SomersetKingsmead4,111Bath1,0764451,4550770003,053
Bath and North East SomersetLambridge4,097Bath1,0794921,3950760003,042
Bath and North East SomersetLansdown3,472Bath1,2722271,0200600002,579
Bath and North East SomersetLyncombe4,101Bath1,3122411,4230690003,045
Bath and North East SomersetNewbridge4,461Bath1,3213841,5400690003,314
Bath and North East SomersetOdd Down4,269Bath1,0324321,6460610003,171
Bath and North East SomersetOldfield4,371Bath9456801,5530670003,245
Bath and North East SomersetPeasedown5,290Somerset North East1,8701,63733708900744,007
Bath and North East SomersetSouthdown4,170Bath9494551,6320600003,096
Bath and North East SomersetTwerton4,006Bath6277681,5220580002,975
Bath and North East SomersetWalcot4,447Bath9436411,6300890003,303
Bath and North East SomersetWestmoreland4,894Bath1,0936371,80001040003,634
Bath and North East SomersetWeston4,028Bath1,3603141,2540630002,991
Bath and North East SomersetWidcombe4,369Bath1,2313881,5470780003,244
 Total80,406 23,12710,76024,52101,3890011559,912

And these are the implied results for 2017 for the new seat of Bath. Please note that the wards used are those of 2015 in order to be consistent with those used by the Boundary Commissions.


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