Castle Point: New Boundaries 2018 Calculation

Castle Point: Overview

Projection: CON seat

Implied MP at 2017:Rebecca Harris  (CON)
County/Area:Essex (Anglia)
Electorate:78,440
Turnout:64.3%

PartyImplied 2017 VotesImplied 2017 Share
CON32,00663.5%
LAB14,37228.5%
UKIP2,7355.4%
LIB1,0822.1%
Green1800.4%
OTH570.1%
CON Majority17,63435.0%

See overview of other seats in Anglia.



Introduction

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Castle Point 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.

Castle Point: Map

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

List of old seats forming part of Castle Point

The old seat(s) needed are:

Old seat: Basildon South and East Thurrock

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

Old seat: Basildon South and East ThurrockTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
BasildonLangdon Hills6,814Basildon and East Thurrock2,8151,0741033226400194,397
BasildonNethermayne8,486Basildon and East Thurrock3,0811,9551703979400795,776
BasildonPitsea North West8,900Castle Point3,0732,4611084059200276,166
BasildonPitsea South East8,469Castle Point3,0622,0941093578800305,740
BasildonVange6,547Basildon and East Thurrock2,3372,063762947200484,890
ThurrockCorringham and Fobbing4,326Basildon and East Thurrock1,667730181763400202,645
ThurrockEast Tilbury4,536Basildon and East Thurrock1,817897212764200463,099
ThurrockOrsett4,823Basildon and East Thurrock2,134557211923300122,949
ThurrockStanford East and Corringham Town6,307Basildon and East Thurrock2,3681,432313156000284,234
ThurrockStanford-le-Hope West4,550Basildon and East Thurrock1,861950341924500233,105
ThurrockThe Homesteads6,434Basildon and East Thurrock2,5981,107402685500524,120
 Total70,192 26,81315,3207313,1946790038447,121

The full details of these calculations are given on the Basildon South and East Thurrock seat details page. Click on "Show workings".

Old seat: Castle Point

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

Old seat: Castle PointTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Castle PointAppleton5,311Castle Point2,3108078823200003,437
Castle PointBoyce5,133Castle Point2,4576418323100003,412
Castle PointCanvey Island Central4,959Castle Point2,2171,0215511900003,412
Castle PointCanvey Island East4,740Castle Point2,2438316211600003,252
Castle PointCanvey Island North5,090Castle Point2,1619546011800003,293
Castle PointCanvey Island South4,960Castle Point2,4038016411800003,386
Castle PointCanvey Island West3,679Castle Point1,661585388000002,364
Castle PointCanvey Island Winter Gardens4,870Castle Point2,3331,1608012500003,698
Castle PointCedar Hall4,663Castle Point1,9816767120000002,928
Castle PointSt George's4,495Castle Point1,8907867419800002,948
Castle PointSt James5,259Southend West and Hadleigh2,22875410521700003,304
Castle PointSt Mary's4,853Castle Point2,01877611021400003,118
Castle PointSt Peter's5,008Castle Point2,1977798022200003,278
Castle PointVictoria4,521Southend West and Hadleigh1,9796347819100002,882
 Total67,541 30,07811,2051,0482,381000044,712

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

New seat: Castle Point

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

New seat: Castle Point
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
BasildonPitsea North West9,623Basildon South and East Thurrock3,0732,4611084059200276,166
BasildonPitsea South East8,957Basildon South and East Thurrock3,0622,0941093578800305,740
Castle PointAppleton5,342Castle Point2,3108078823200003,437
Castle PointBoyce5,300Castle Point2,4576418323100003,412
Castle PointCanvey Island Central5,302Castle Point2,2171,0215511900003,412
Castle PointCanvey Island East5,054Castle Point2,2438316211600003,252
Castle PointCanvey Island North5,117Castle Point2,1619546011800003,293
Castle PointCanvey Island South5,263Castle Point2,4038016411800003,386
Castle PointCanvey Island West3,672Castle Point1,661585388000002,364
Castle PointCanvey Island Winter Gardens5,744Castle Point2,3331,1608012500003,698
Castle PointCedar Hall4,549Castle Point1,9816767120000002,928
Castle PointSt George's4,579Castle Point1,8907867419800002,948
Castle PointSt Mary's4,844Castle Point2,01877611021400003,118
Castle PointSt Peter's5,094Castle Point2,1977798022200003,278
 Total78,440 32,00614,3721,0822,735180005750,432

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