Brighton Kemptown and Seahaven: New Boundaries 2018 Calculation

Brighton Kemptown and Seahaven: Overview

Projection: CON seat

Implied MP at 2017:Unknown (changed seat)  (CON)
County/Area:East Sussex (South East)
Electorate:79,036
Turnout:73.9%

PartyImplied 2017 VotesImplied 2017 Share
CON25,80044.2%
LAB22,29438.2%
LIB10,20517.5%
OTH1060.2%
CON Majority3,5066.0%

See overview of other seats in South East.



Introduction

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Brighton Kemptown and Seahaven 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.

Brighton Kemptown and Seahaven: Map

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

List of old seats forming part of Brighton Kemptown and Seahaven

The old seat(s) needed are:

Old seat: Brighton Kemptown

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

Old seat: Brighton KemptownTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Brighton and HoveEast Brighton9,318Brighton Kemptown and Seahaven2,0865,2372010000317,555
Brighton and HoveMoulsecoomb and Bevendean9,998Brighton Pavilion2,5886,5271740000859,374
Brighton and HoveQueen's Park10,037Brighton Kemptown and Seahaven;
Brighton Pavilion
2,0835,5714110000488,113
Brighton and HoveRottingdean Coastal10,224Brighton Kemptown and Seahaven3,8433,281207000097,340
Brighton and HoveWoodingdean7,216Brighton Kemptown and Seahaven2,6062,5211180000165,261
LewesEast Saltdean and Telscombe Cliffs5,275Brighton Kemptown and Seahaven1,9371,859126000063,928
LewesPeacehaven East3,825Brighton Kemptown and Seahaven1,2901,28756000032,636
LewesPeacehaven North3,148Brighton Kemptown and Seahaven1,2091,24881000092,547
LewesPeacehaven West3,164Brighton Kemptown and Seahaven1,1941,17382000042,453
 Total62,205 18,83628,7041,456000021149,207

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

Old seat: Lewes

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

Old seat: LewesTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
LewesBarcombe and Hamsey1,510Lewes and West Wealden69973537000001,309
LewesChailey and Wivelsfield3,802Lewes and West Wealden1,997147998000003,142
LewesDitchling and Westmeston1,891Lewes and West Wealden1,02956383000001,468
LewesKingston1,542Lewes and West Wealden64853581000001,282
LewesLewes Bridge3,356Lewes and West Wealden1,0796001,235000002,914
LewesLewes Castle3,283Lewes and West Wealden1,0856601,239000002,984
LewesLewes Priory5,067Lewes and West Wealden2,0149221,809000004,745
LewesNewhaven Denton and Meeching5,532Brighton Kemptown and Seahaven2,0108422,185000005,037
LewesNewhaven Valley2,554Brighton Kemptown and Seahaven9493321,194000002,475
LewesNewick1,922Lewes and West Wealden96159457000001,477
LewesOuse Valley and Ringmer4,829Lewes and West Wealden2,0202851,653000003,958
LewesPlumpton, Streat, East Chiltington and St John (Without)1,678Lewes and West Wealden74661598000001,405
LewesSeaford Central3,500Brighton Kemptown and Seahaven1,3953771,205000002,977
LewesSeaford East3,792Brighton Kemptown and Seahaven1,5382401,116000002,894
LewesSeaford North3,913Brighton Kemptown and Seahaven1,5443421,318000003,204
LewesSeaford South3,480Brighton Kemptown and Seahaven1,3611801,049000002,590
LewesSeaford West3,743Brighton Kemptown and Seahaven1,6351561,030000002,821
WealdenAlfriston1,942Lewes and West Wealden82460531000001,415
WealdenEast Dean1,876Lewes and West Wealden90352436000001,391
WealdenPolegate North4,507Lewes and West Wealden1,6193881,199000003,206
WealdenPolegate South1,988Lewes and West Wealden763177559000001,499
 Total65,707 26,8196,06221,3120000054,193

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

New seat: Brighton Kemptown and Seahaven

The new seat of Brighton Kemptown and Seahaven is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Brighton Kemptown and Seahaven
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Brighton and HoveEast Brighton10,425Brighton Kemptown2,0865,2372010000317,555
Brighton and HoveQueen's Park6,467Brighton Kemptown1,2033,2192370000284,687
Brighton and HoveRottingdean Coastal10,127Brighton Kemptown3,8433,281207000097,340
Brighton and HoveWoodingdean7,260Brighton Kemptown2,6062,5211180000165,261
LewesEast Saltdean and Telscombe Cliffs5,422Brighton Kemptown1,9371,859126000063,928
LewesNewhaven Denton and Meeching6,596Lewes2,0108422,185000005,037
LewesNewhaven Valley3,241Lewes9493321,194000002,475
LewesPeacehaven East3,636Brighton Kemptown1,2901,28756000032,636
LewesPeacehaven North3,514Brighton Kemptown1,2091,24881000092,547
LewesPeacehaven West3,383Brighton Kemptown1,1941,17382000042,453
LewesSeaford Central3,897Lewes1,3953771,205000002,977
LewesSeaford East3,789Lewes1,5382401,116000002,894
LewesSeaford North4,195Lewes1,5443421,318000003,204
LewesSeaford South3,391Lewes1,3611801,049000002,590
LewesSeaford West3,693Lewes1,6351561,030000002,821
 Total79,036 25,80022,29410,205000010658,405

And these are the implied results for 2017 for the new seat of Brighton Kemptown and Seahaven. 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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