Windsor: New Boundaries 2018 Calculation

Windsor: Overview

Projection: CON seat

Implied MP at 2017:Adam Afriyie  (CON)
County/Area:Berkshire (South East)
Electorate:76,930
Turnout:73.2%

PartyImplied 2017 VotesImplied 2017 Share
CON36,46764.8%
LAB12,68322.5%
LIB5,64810.0%
Green1,5112.7%
CON Majority23,78442.2%

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 Windsor 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.

Windsor: Map

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

List of old seats forming part of Windsor

The old seat(s) needed are:

Old seat: Surrey Heath

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

Old seat: Surrey HeathTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
GuildfordAsh South and Tongham5,958Surrey Heath2,66289749901540004,212
GuildfordAsh Vale4,276Surrey Heath1,84262049901170003,078
GuildfordAsh Wharf4,717Surrey Heath1,95872153901260003,344
Surrey HeathBagshot4,411Surrey Heath1,88257734802560003,063
Surrey HeathBisley2,610Surrey Heath1,5893491650730002,176
Surrey HeathChobham2,895Surrey Heath1,4933631390750002,070
Surrey HeathFrimley4,444Surrey Heath2,11189524501110003,362
Surrey HeathFrimley Green4,249Surrey Heath1,87663057601190003,201
Surrey HeathHeatherside4,479Surrey Heath2,22657739701180003,318
Surrey HeathLightwater5,260Surrey Heath2,44862241802290003,717
Surrey HeathMytchett and Deepcut4,929Surrey Heath2,32770564101360003,809
Surrey HeathOld Dean3,012Surrey Heath1,1841,1241730840002,565
Surrey HeathParkside4,791Surrey Heath2,43951531601130003,383
Surrey HeathSt Michaels3,508Surrey Heath1,5669972070980002,868
Surrey HeathSt Pauls4,452Surrey Heath2,4713881760920003,127
Surrey HeathTown3,378Surrey Heath1,8126042440970002,757
Surrey HeathWatchetts3,652Surrey Heath1,7337721880900002,783
Surrey HeathWest End3,308Surrey Heath1,7504682870940002,599
Surrey HeathWindlesham3,256Windsor1,7493512150780002,393
 Total77,585 37,11812,1756,27202,26000057,825

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

Old seat: Windsor

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

Old seat: WindsorTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Bracknell ForestAscot3,967Windsor2,00263127901320003,044
Bracknell ForestBinfield with Warfield6,444Windsor3,0601,1423040760004,582
Bracknell ForestWarfield Harvest Ride5,755Windsor2,91389228201740004,261
Bracknell ForestWinkfield and Cranbourne3,883Windsor1,81345215601050002,526
SloughColnbrook with Poyle3,404Windsor1,5771,3952150550003,242
Windsor and MaidenheadAscot and Cheapside3,643Windsor2,08349528901130002,980
Windsor and MaidenheadCastle Without4,418Windsor2,0959215580860003,660
Windsor and MaidenheadClewer East3,465Windsor1,6796255150540002,873
Windsor and MaidenheadClewer North5,341Windsor2,6859743240820004,065
Windsor and MaidenheadClewer South3,406Windsor1,7046963520420002,794
Windsor and MaidenheadDatchet3,368Windsor1,5386183770450002,578
Windsor and MaidenheadEton and Castle1,227Windsor8702832850400001,478
Windsor and MaidenheadEton Wick1,711Windsor673407890220001,191
Windsor and MaidenheadHorton and Wraysbury3,723Windsor1,9244842160420002,666
Windsor and MaidenheadOld Windsor3,573Windsor1,8245582060520002,640
Windsor and MaidenheadPark3,536Windsor1,77656733801170002,798
Windsor and MaidenheadSunningdale3,489Windsor2,0864412640430002,834
Windsor and MaidenheadSunninghill and South Ascot4,481Windsor2,41675138401530003,704
 Total68,834 34,71812,3325,43301,43300053,916

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

New seat: Windsor

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

New seat: Windsor
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Bracknell ForestAscot4,155Windsor2,00263127901320003,044
Bracknell ForestBinfield with Warfield6,253Windsor3,0601,1423040760004,582
Bracknell ForestWarfield Harvest Ride5,816Windsor2,91389228201740004,261
Bracknell ForestWinkfield and Cranbourne3,450Windsor1,81345215601050002,526
SloughColnbrook with Poyle4,426Windsor1,5771,3952150550003,242
Surrey HeathWindlesham3,333Surrey Heath1,7493512150780002,393
Windsor and MaidenheadAscot and Cheapside4,068Windsor2,08349528901130002,980
Windsor and MaidenheadCastle Without4,995Windsor2,0959215580860003,660
Windsor and MaidenheadClewer East3,921Windsor1,6796255150540002,873
Windsor and MaidenheadClewer North5,550Windsor2,6859743240820004,065
Windsor and MaidenheadClewer South3,814Windsor1,7046963520420002,794
Windsor and MaidenheadDatchet3,520Windsor1,5386183770450002,578
Windsor and MaidenheadEton and Castle2,019Windsor8702832850400001,478
Windsor and MaidenheadEton Wick1,625Windsor673407890220001,191
Windsor and MaidenheadHorton and Wraysbury3,639Windsor1,9244842160420002,666
Windsor and MaidenheadOld Windsor3,603Windsor1,8245582060520002,640
Windsor and MaidenheadPark3,819Windsor1,77656733801170002,798
Windsor and MaidenheadSunningdale3,868Windsor2,0864412640430002,834
Windsor and MaidenheadSunninghill and South Ascot5,056Windsor2,41675138401530003,704
 Total76,930 36,46712,6835,64801,51100056,309

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