Glenshane: New Boundaries 2018 Calculation

Glenshane: Overview

 Projection: SF seat 

Implied MP at 2017: Unknown (changed seat)  (SF)
County/Area: Londonderry (Northern Ireland)
Electorate: 73,833
Turnout: 63.6%

 Implied 2017 VotesImplied 2017 Share
SF20,10042.8%
DUP17,55137.4%
SDLP4,6419.9%
UUP2,5495.4%
MIN1,9284.1%
OTH1740.4%
SF Majority2,5495.4%

See overview of other seats in Northern Ireland.

Glenshane: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015

Introduction

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

List of old seats forming part of Glenshane

The old seat(s) needed are:

Old seat: Foyle

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

Old seat: FoyleTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Derry and StrabaneBallymagroarty2,911Foyle0904660079089551,904
Derry and StrabaneBrandywell2,468Foyle0567450090361371,613
Derry and StrabaneCarn Hill2,237Foyle0685340067046281,463
Derry and StrabaneCaw2,985Foyle06596730057428171,951
Derry and StrabaneCity Walls2,405Foyle0553440087959361,571
Derry and StrabaneClaudy13Glenshane033003009
Derry and StrabaneClondermot2,478Foyle05485580047623141,619
Derry and StrabaneCreggan2,362Foyle0544430086458361,545
Derry and StrabaneCreggan South2,212Foyle0509400081054331,446
Derry and StrabaneCulmore2,954Foyle0904440088560371,930
Derry and StrabaneDrumahoe2,936Foyle06476620056528171,919
Derry and StrabaneEbrington2,762Foyle06096230053126161,805
Derry and StrabaneEglinton2,731Foyle05706510048748301,786
Derry and StrabaneEnagh2,862Foyle05986820051050311,871
Derry and StrabaneFoyle Springs2,225Foyle0690500060468421,454
Derry and StrabaneGalliagh2,891Foyle0886430086659361,890
Derry and StrabaneKilfennan2,911Foyle06436560056027171,903
Derry and StrabaneLisnagelvin2,485Foyle05485600047924151,626
Derry and StrabaneMadam's Bank2,530Foyle0785570068877481,655
Derry and StrabaneNew Buildings2,544Foyle05316070045345281,664
Derry and StrabaneNorthland3,140Foyle0974710085396592,053
Derry and StrabaneShantallow2,470Foyle0756370074050311,614
Derry and StrabaneShantallow East3,004Foyle0920450090061381,964
Derry and StrabaneSheriff's Mountain2,507Foyle0577460091662381,639
Derry and StrabaneSkeoge2,835Foyle0868430084958351,853
Derry and StrabaneSlievekirk1,487Foyle0310354002652616971
Derry and StrabaneSpringtown2,261Foyle0702510061469421,478
Derry and StrabaneVictoria2,717Foyle06006120052226161,776
 Total70,323 018,0907,4000018,2561,37884845,972

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

Old seat: Londonderry East

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

Old seat: Londonderry EastTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Causeway Coast and GlensAghadowey2,372Glenshane1941198300021780101,450
Causeway Coast and GlensAltahullion2,185Glenshane015039300656122161,337
Causeway Coast and GlensAtlantic2,869Dalriada1971021,174000251331,757
Causeway Coast and GlensBallykelly2,110Glenshane014537900635118151,292
Causeway Coast and GlensCastlerock2,345Dalriada1911188200021580101,434
Causeway Coast and GlensChurchland2,519Dalriada13025552000627911,542
Causeway Coast and GlensCoolessan2,018Glenshane83117736002613441,235
Causeway Coast and GlensDrumsurn2,362Glenshane97137860003064051,445
Causeway Coast and GlensDundooan2,460Dalriada168881,006000215281,505
Causeway Coast and GlensDungiven2,174Glenshane014938900654121161,329
Causeway Coast and GlensFeeny2,283Glenshane015740900687127171,397
Causeway Coast and GlensGarvagh2,299Glenshane1871158040021178101,405
Causeway Coast and GlensGreysteel2,945Glenshane020252900885164211,801
Causeway Coast and GlensGreystone2,168Glenshane90125791002803751,328
Causeway Coast and GlensHopefield2,516Dalriada172891,029000220291,539
Causeway Coast and GlensKilrea2,314Glenshane1891178090021279101,416
Causeway Coast and GlensMacosquin2,009Glenshane164101704001856891,231
Causeway Coast and GlensMagilligan2,514Glenshane104146916003264261,540
Causeway Coast and GlensMountsandel2,484Dalriada12825151200618911,519
Causeway Coast and GlensPortrush and Dunluce1,977Dalriada13570810000173221,210
Causeway Coast and GlensPortstewart2,260Dalriada15581924000197261,383
Causeway Coast and GlensQuarry2,722Dalriada141275562006771011,666
Causeway Coast and GlensRoeside1,993Glenshane82115726002583441,219
Causeway Coast and GlensUniversity2,698Dalriada14027355800672911,653
Causeway Coast and GlensWaterside2,983Dalriada154301615007421111,824
Causeway Coast and GlensWindy Hall2,741Dalriada142277565006821011,677
Derry and StrabaneClaudy2,333Glenshane552067870028188111,428
Derry and StrabanePark2,384Glenshane3713956400593112151,460
 Total67,037 3,1354,42019,7210010,8802,53832841,022

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

Old seat: Ulster Mid

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

Old seat: Ulster MidTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Mid UlsterArdboe2,508Tyrone North96206372009993801,711
Mid UlsterBallygawley406Fermanagh and South Tyrone29251090011300276
Mid UlsterBallymaguigan2,687Glenshane130166490001,046001,832
Mid UlsterBellaghy2,442Glenshane11815044700951001,666
Mid UlsterCastlecaulfield694Fermanagh and South Tyrone50431860019400473
Mid UlsterCastledawson2,466Glenshane11915245100960001,682
Mid UlsterCoagh2,216Tyrone North149120415007913501,510
Mid UlsterCoalisland North2,414Upper Bann and Blackwater92199357009613701,646
Mid UlsterCoalisland South2,791Upper Bann and Blackwater107229414001,1104301,903
Mid UlsterCookstown East2,137Tyrone North144116400007633301,456
Mid UlsterCookstown South2,443Tyrone North165132458008723801,665
Mid UlsterCookstown West2,430Tyrone North164132456008673801,657
Mid UlsterCoolshinny2,371Glenshane76166638006538401,617
Mid UlsterDonaghmore2,507Tyrone North96206370009983801,708
Mid UlsterDraperstown2,031Glenshane9812537100791001,385
Mid UlsterGlebe2,543Glenshane81179684007009001,734
Mid UlsterKillyman413Upper Bann and Blackwater241711700100230281
Mid UlsterKillymeal230Upper Bann and Blackwater139660056130157
Mid UlsterLissan2,441Glenshane78172657006728701,666
Mid UlsterLoughry1,951Tyrone North132106365006963101,330
Mid UlsterLower Glenshane1,974Glenshane49132236009042501,346
Mid UlsterMaghera2,543Glenshane63172304001,1653201,736
Mid UlsterOaklands2,098Tyrone North141114394007493301,431
Mid UlsterPomeroy2,592Tyrone North175140486009244101,766
Mid UlsterStewartstown2,117Tyrone North81174314008423301,444
Mid UlsterSwatragh2,301Glenshane57155275001,0542901,570
Mid UlsterTamlaght O'Crilly2,430Glenshane60164290001,1133001,657
Mid UlsterThe Loup2,512Glenshane81176675006928901,713
Mid UlsterTobermore2,426Glenshane11714944400944001,654
Mid UlsterTown Parks East2,487Glenshane80175668006858801,696
Mid UlsterValley2,447Glenshane60165292001,1203001,667
Mid UlsterWashing Bay2,434Upper Bann and Blackwater93200360009683701,658
 Total68,482 3,0184,56612,5610025,4531,095046,693

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

New seat: Glenshane

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

New seat: Glenshane
DistrictWardElectorate
2017
Old Seat UUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Causeway Coast and GlensAghadowey2,511Londonderry East1941198300021780101,450
Causeway Coast and GlensAltahullion2,190Londonderry East015039300656122161,337
Causeway Coast and GlensBallykelly2,302Londonderry East014537900635118151,292
Causeway Coast and GlensCoolessan2,024Londonderry East83117736002613441,235
Causeway Coast and GlensDrumsurn2,338Londonderry East97137860003064051,445
Causeway Coast and GlensDungiven2,385Londonderry East014938900654121161,329
Causeway Coast and GlensFeeny2,276Londonderry East015740900687127171,397
Causeway Coast and GlensGarvagh2,272Londonderry East1871158040021178101,405
Causeway Coast and GlensGreysteel2,876Londonderry East020252900885164211,801
Causeway Coast and GlensGreystone2,290Londonderry East90125791002803751,328
Causeway Coast and GlensKilrea2,513Londonderry East1891178090021279101,416
Causeway Coast and GlensMacosquin2,373Londonderry East164101704001856891,231
Causeway Coast and GlensMagilligan2,254Londonderry East104146916003264261,540
Causeway Coast and GlensRoeside2,071Londonderry East82115726002583441,219
Derry and StrabaneClaudy14Foyle014002007
Derry and StrabaneClaudy2,505Londonderry East552087860028288111,430
Derry and StrabanePark2,477Londonderry East3713956400593112151,460
Mid UlsterBallymaguigan2,595Ulster Mid130166490001,046001,832
Mid UlsterBellaghy2,537Ulster Mid11815044700951001,666
Mid UlsterCastledawson2,499Ulster Mid11915245100960001,682
Mid UlsterCoolshinny2,535Ulster Mid76166638006538401,617
Mid UlsterDraperstown2,040Ulster Mid9812537100791001,385
Mid UlsterGlebe2,371Ulster Mid81179684007009001,734
Mid UlsterLissan2,441Ulster Mid78172657006728701,666
Mid UlsterLower Glenshane2,233Ulster Mid49132236009042501,346
Mid UlsterMaghera2,263Ulster Mid63172304001,1653201,736
Mid UlsterSwatragh2,360Ulster Mid57155275001,0542901,570
Mid UlsterTamlaght O'Crilly2,449Ulster Mid60164290001,1133001,657
Mid UlsterThe Loup2,684Ulster Mid81176675006928901,713
Mid UlsterTobermore2,463Ulster Mid11714944400944001,654
Mid UlsterTown Parks East2,303Ulster Mid80175668006858801,696
Mid UlsterValley2,389Ulster Mid60165292001,1203001,667
 Total73,833 2,5494,64117,5510020,1001,92817446,943

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


© 2017 Martin Baxter
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