Down North: New Boundaries 2018 Calculation

Down North: Overview

 Projection: MIN seat 

Implied MP at 2015: Lady Sylvia Hermon  (MIN)
County/Area: Down (Northern Ireland)
Electorate: 73,645
Turnout: 56.3%

 Implied 2015 VotesImplied 2015 Share
MIN19,80947.7%
LIB11,73228.3%
OTH5,71913.8%
Green2,2985.5%
UKIP1,4563.5%
LAB2800.7%
NAT2030.5%
MIN Majority8,07719.5%

See overview of other seats in Northern Ireland.

Down North: 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 2015 had the new boundaries for Down North 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 2015. 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 Down North

The old seat(s) needed are:

Old seat: Belfast East

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

Old seat: Belfast EastTransfer-adjusted Results
DistrictWardElectorate
2015
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
BelfastBallymacarrett3,741Belfast East0161,28300105887592,350
BelfastBeersbridge4,406Belfast East0191,511001241,044692,767
BelfastBelmont3,329Belfast East00850010111,068712,091
BelfastBloomfield4,113Belfast East0181,41000116976642,584
BelfastConnswater3,892Belfast East0171,33500110923612,446
BelfastCregagh1,553Belfast East07532004436924976
BelfastGarnerville3,142Belfast East0080309511,008671,974
BelfastGilnahirk3,462Belfast East00884010511,111732,174
BelfastHillfoot1,422Belfast East06488004033822894
BelfastKnock3,501Belfast East00894010711,124742,200
BelfastMerok2,994Belfast East0131,0270084710471,881
BelfastOrangefield3,237Belfast East0141,1100091768512,034
BelfastSandown3,075Belfast East007860941987651,933
BelfastShandon3,497Belfast East00893010711,122742,197
BelfastStormont3,380Belfast East00863010311,085722,124
BelfastSydenham3,564Belfast East0151,22200100846562,239
BelfastWoodstock48Belfast East001700111130
Lisburn and CastlereaghBallyhanwood1,904Down North006450610459301,195
Lisburn and CastlereaghCarrowreagh2,540Down North008620810612401,595
Lisburn and CastlereaghDundonald2,071Down North007030670499331,302
Lisburn and CastlereaghEnler2,203Down North007480710531351,385
Lisburn and CastlereaghGraham's Bridge2,079Down North007060670501331,307
 Total63,153 012519,57201,05982216,9791,12139,678

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

Old seat: Down North

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

Old seat: Down NorthTransfer-adjusted Results
DistrictWardElectorate
2015
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
BelfastGarnerville219Belfast East00247626421124
North Down and ArdsBallycrochan2,187Down North00298793376111971,225
North Down and ArdsBallygrainey3,413Down North00402130101109593091,911
North Down and ArdsBallyholme2,638Down North003111007887412391,477
North Down and ArdsBallymagee2,961Down North0040410745108272671,660
North Down and ArdsBloomfield2,893Down North003411108588122621,618
North Down and ArdsBroadway2,613Down North003081007777342371,463
North Down and ArdsBryansburn2,581Down North026346166597442401,446
North Down and ArdsCarrowdore841Strangford032167702917857470
North Down and ArdsCastle2,858Down North003371098588032591,601
North Down and ArdsClandeboye2,641Down North02735519154106922231,480
North Down and ArdsCultra2,676Down North02735919156107012261,498
North Down and ArdsDonaghadee2,924Down North003991064498162631,637
North Down and ArdsGroomsport2,564Down North00350923887162311,435
North Down and ArdsHarbour3,290Down North003871279799242981,842
North Down and ArdsHelen's Bay2,550Down North02634318149106672151,428
North Down and ArdsHolywood3,140Down North03242222183128222651,758
North Down and ArdsKilcooley3,007Down North0304041976108662791,684
North Down and ArdsLoughries1,155Strangford0452291003924579647
North Down and ArdsLoughview3,438Down North03546225201139002901,926
North Down and ArdsRathgael2,457Down North024329156287082281,374
North Down and ArdsRathmore2,606Down North026350166597522421,460
North Down and ArdsSilverbirch3,010Down North0041110845108402711,685
North Down and ArdsSilverstream2,733Down North027367176997872541,530
North Down and ArdsWarren2,812Down North003831024397852531,575
 Total64,207 03578,4881,4801,95727317,6945,70535,954

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

New seat: Down North

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

New seat: Down North
DistrictWardElectorate
2015
Old Seat UUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Lisburn and CastlereaghBallyhanwood2,208Belfast East006450610459301,195
Lisburn and CastlereaghCarrowreagh3,054Belfast East008620810612401,595
Lisburn and CastlereaghDundonald2,223Belfast East007030670499331,302
Lisburn and CastlereaghEnler2,156Belfast East007480710531351,385
Lisburn and CastlereaghGraham's Bridge2,120Belfast East007060670501331,307
North Down and ArdsBallycrochan2,578Down North00298793376111971,225
North Down and ArdsBallygrainey3,173Down North00402130101109593091,911
North Down and ArdsBallyholme2,865Down North003111007887412391,477
North Down and ArdsBallymagee2,968Down North0040410745108272671,660
North Down and ArdsBloomfield2,778Down North003411108588122621,618
North Down and ArdsBroadway2,743Down North003081007777342371,463
North Down and ArdsBryansburn2,837Down North026346166597442401,446
North Down and ArdsCastle2,747Down North003371098588032591,601
North Down and ArdsClandeboye2,692Down North02735519154106922231,480
North Down and ArdsCultra2,888Down North02735919156107012261,498
North Down and ArdsDonaghadee2,864Down North003991064498162631,637
North Down and ArdsGroomsport2,831Down North00350923887162311,435
North Down and ArdsHarbour2,979Down North003871279799242981,842
North Down and ArdsHelen's Bay2,765Down North02634318149106672151,428
North Down and ArdsHolywood3,089Down North03242222183128222651,758
North Down and ArdsKilcooley2,689Down North0304041976108662791,684
North Down and ArdsLoughview2,820Down North03546225201139002901,926
North Down and ArdsRathgael2,440Down North024329156287082281,374
North Down and ArdsRathmore2,864Down North026350166597522421,460
North Down and ArdsSilverbirch2,841Down North0041110845108402711,685
North Down and ArdsSilverstream2,508Down North027367176997872541,530
North Down and ArdsWarren2,925Down North003831024397852531,575
 Total73,645 028011,7321,4562,29820319,8095,71941,497

And these are the implied results for 2015 for the new seat of Down North.


© 2017 Martin Baxter
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