Colchester: New Boundaries 2018 Calculation

Colchester: Overview

Projection: CON seat

Implied MP at 2017:Will Quince  (CON)
County/Area:Essex (Anglia)
Electorate:82,075
Turnout:67.1%

PartyImplied 2017 VotesImplied 2017 Share
CON25,20945.8%
LAB19,60435.6%
LIB9,15516.6%
Green8631.6%
OTH1800.3%
UKIP300.1%
CON Majority5,60510.2%

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 Colchester 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.

Colchester: Map

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

List of old seats forming part of Colchester

The old seat(s) needed are:

Old seat: Colchester

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

Old seat: ColchesterTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ColchesterBerechurch6,424Colchester1,6792,25946505700154,475
ColchesterCastle6,662Colchester2,4071,5848930970094,990
ColchesterChrist Church3,275Colchester1,0686364240480072,183
ColchesterHighwoods6,732Colchester2,5331,74957408300464,985
ColchesterLexden4,118Colchester1,6856983620420062,793
ColchesterMile End7,104Colchester2,6431,4961,0500740085,271
ColchesterNew Town6,223Colchester1,7271,7631,06708600394,682
ColchesterOld Heath4,126Colchester1,1591,1587140460073,084
ColchesterPrettygate5,794Colchester2,1769645080500063,704
ColchesterShrub End7,224Colchester2,6241,5348500570075,072
ColchesterSt Andrew's4,861Colchester1,8742,91859108500155,483
ColchesterSt Anne's5,834Colchester1,9041,4829850700084,449
ColchesterSt John's3,918Colchester1,0866476060330052,377
 Total72,295 24,56518,8889,08908280017853,548

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

Old seat: Harwich and North Essex

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

Old seat: Harwich and North EssexTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ColchesterDedham and Langham2,334Essex North East1,1953008828350051,651
ColchesterEast Donyland1,845Colchester6447166630350021,493
ColchesterFordham and Stour4,180Essex North East2,07461117953650042,986
ColchesterGreat Tey2,138Essex North East99830011366310011,509
ColchesterPyefleet2,087Essex North East1,0262878126350011,456
ColchesterWest Bergholt and Eight Ash Green3,822Essex North East1,8176341831366700132,850
ColchesterWest Mersea5,747Essex North East2,6148832152089800104,028
ColchesterWivenhoe Cross1,627Essex North East1,193919298116860032,615
ColchesterWivenhoe Quay4,049Essex North East1,4691,12626652920033,008
TendringAlresford1,677Essex North East64629714525140021,129
TendringArdleigh and Little Bromley1,846Essex North East9173002823100011,279
TendringBradfield, Wrabness and Wix1,828Essex North East8113243165130051,249
TendringBrightlingsea6,398Essex North East2,6971,31720210616000484,530
TendringGreat and Little Oakley1,655Harwich and Clacton7293413483120081,207
TendringGreat Bentley1,751Essex North East83626611026140041,256
TendringHarwich East1,779Harwich and Clacton59279049372100101,499
TendringHarwich East Central3,656Harwich and Clacton1,2711,28898148340042,843
TendringHarwich West3,902Harwich and Clacton1,4231,08394161270042,792
TendringHarwich West Central3,792Harwich and Clacton1,2901,2949563300042,776
TendringLawford3,364Essex North East1,4867458550560032,425
TendringManningtree, Mistley, Little Bentley and Tendring3,562Essex North East1,7176668851650022,589
TendringRamsey and Parkeston1,677Harwich and Clacton6805174382150031,340
TendringThorrington, Frating, Elmstead and Great Bromley3,724Essex North East1,79656019852270022,635
 Total68,440 29,92115,5642,7891,6871,0420014251,145

The full details of these calculations are given on the Harwich and North Essex seat details page. Click on "Show workings".

New seat: Colchester

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

New seat: Colchester
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
ColchesterBerechurch6,685Colchester1,6792,25946505700154,475
ColchesterCastle7,453Colchester2,4071,5848930970094,990
ColchesterChrist Church3,259Colchester1,0686364240480072,183
ColchesterEast Donyland2,080Harwich and North Essex6447166630350021,493
ColchesterHighwoods7,447Colchester2,5331,74957408300464,985
ColchesterLexden4,173Colchester1,6856983620420062,793
ColchesterMile End7,876Colchester2,6431,4961,0500740085,271
ColchesterNew Town6,993Colchester1,7271,7631,06708600394,682
ColchesterOld Heath4,608Colchester1,1591,1587140460073,084
ColchesterPrettygate5,533Colchester2,1769645080500063,704
ColchesterShrub End7,577Colchester2,6241,5348500570075,072
ColchesterSt Andrew's8,192Colchester1,8742,91859108500155,483
ColchesterSt Anne's6,648Colchester1,9041,4829850700084,449
ColchesterSt John's3,551Colchester1,0866476060330052,377
 Total82,075 25,20919,6049,155308630018055,041

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