Luton South: New Boundaries 2018 Calculation

Luton South: Overview

Projection: LAB seat

Implied MP at 2017:Gavin Shuker  (LAB)
County/Area:Bedfordshire (Anglia)
Electorate:74,715
Turnout:68.8%

PartyImplied 2017 VotesImplied 2017 Share
LAB31,21560.7%
CON17,44233.9%
LIB1,2252.4%
UKIP7951.5%
Green5371.0%
OTH1720.3%
LAB Majority13,77326.8%

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 Luton South 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.

Luton South: Map

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

List of old seats forming part of Luton South

The old seat(s) needed are:

Old seat: Bedfordshire South West

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

Old seat: Bedfordshire South WestTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Central BedfordshireCaddington2,845Luton South1,1523993803600131,638
Central BedfordshireDunstable-Central3,332Bedfordshire South West1,4348437502700142,393
Central BedfordshireDunstable-Icknield5,731Bedfordshire South West2,6441,37212604200234,207
Central BedfordshireDunstable-Manshead3,575Bedfordshire South West1,4621,2257702900332,826
Central BedfordshireDunstable-Northfields6,528Bedfordshire South West2,7611,920137011900374,974
Central BedfordshireDunstable-Watling7,402Bedfordshire South West3,6151,47413105200415,313
Central BedfordshireEaton Bray3,292Bedfordshire South West1,6105394902100192,238
Central BedfordshireHeath and Reach3,426Bedfordshire South West1,6434444701800122,164
Central BedfordshireHoughton Hall5,717Luton North and Houghton Regis2,0171,8303220950094,273
Central BedfordshireLeighton Buzzard North10,881Bedfordshire South West4,6082,480417016600207,691
Central BedfordshireLeighton Buzzard South9,303Bedfordshire South West3,8101,943375012900346,291
Central BedfordshireLinslade9,108Bedfordshire South West3,7541,948566016600136,447
Central BedfordshireParkside3,220Luton North and Houghton Regis1,3441,2418402800182,715
Central BedfordshireTithe Farm2,994Luton North and Houghton Regis1,1041,13518602200142,461
 Total77,354 32,95818,7932,63009500030055,631

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

Old seat: Luton North

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

Old seat: Luton NorthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
LutonBarnfield5,295Luton South1,4112,0121280640003,615
LutonBramingham5,366Luton North and Houghton Regis1,6831,569900490003,391
LutonChallney8,227Luton North and Houghton Regis1,6674,3371360980006,238
LutonIcknield5,614Luton North and Houghton Regis1,7821,720900540003,646
LutonLeagrave7,492Luton North and Houghton Regis1,9953,560410670005,663
LutonLewsey8,207Luton North and Houghton Regis1,6544,080820740005,890
LutonLimbury5,530Luton North and Houghton Regis1,3462,264480470003,705
LutonNorthwell4,966Luton North and Houghton Regis1,0432,693480520003,836
LutonSaints8,501Luton North and Houghton Regis1,5155,272310820006,900
LutonSundon Park5,354Luton North and Houghton Regis1,3052,2591140620003,740
 Total64,552 15,40129,766808064900046,624

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

Old seat: Luton South

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

Old seat: Luton SouthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Central BedfordshireCaddington4,422Luton South1,46991922303900222,501
LutonBiscot8,351Luton South1,3725,059116923600526,727
LutonCrawley4,696Luton South1,0551,676106129180052,989
LutonDallow8,243Luton South1,2795,338138443800286,865
LutonFarley6,839Luton South1,4993,35913061340085,091
LutonHigh Town4,206Luton South1,2792,2926254790063,772
LutonRound Green7,566Luton South1,9842,61613869280084,843
LutonSouth6,139Luton South1,8113,6531087312400155,784
LutonStopsley5,294Luton South1,2631,5039948180072,938
LutonWigmore7,985Luton South1,8682,389140195230084,623
 Total63,741 14,87928,8041,0597954370015946,133

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

New seat: Luton South

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

New seat: Luton South
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Central BedfordshireCaddington2,347Bedfordshire South West1,1523993803600131,638
Central BedfordshireCaddington3,644Luton South1,46991922303900222,501
LutonBarnfield5,181Luton North1,4112,0121280640003,615
LutonBiscot9,797Luton South1,3725,059116923600526,727
LutonCrawley4,353Luton South1,0551,676106129180052,989
LutonDallow9,998Luton South1,2795,338138443800286,865
LutonFarley7,414Luton South1,4993,35913061340085,091
LutonHigh Town5,493Luton South1,2792,2926254790063,772
LutonRound Green7,055Luton South1,9842,61613869280084,843
LutonSouth8,423Luton South1,8113,6531087312400155,784
LutonStopsley4,279Luton South1,2631,5039948180072,938
LutonWigmore6,731Luton South1,8682,389140195230084,623
 Total74,715 17,44231,2151,2257955370017251,386

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