Down North: New Boundaries 2018 Calculation

Down North: Overview

 Projection: MIN seat 

Implied MP at 2017: Lady Sylvia Hermon  (MIN)
County/Area: Down (Northern Ireland)
Electorate: 73,645
Turnout: 56.6%

 Implied 2017 VotesImplied 2017 Share
MIN18,63944.7%
DUP18,35744.1%
Green2,7256.5%
OTH1,0482.5%
SF4541.1%
SDLP3120.7%
UUP1200.3%
MIN Majority2820.7%

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 2017 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 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 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
2017
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
BelfastBallymacarrett3,761Belfast East92211,65300114639212,540
BelfastBeersbridge4,430Belfast East109251,94700135753242,993
BelfastBelmont3,347Belfast East82099505311,093352,259
BelfastBloomfield4,135Belfast East101231,81700126704232,794
BelfastConnswater3,913Belfast East96221,72100119665222,645
BelfastCregagh1,561Belfast East389686004726591,054
BelfastGarnerville3,159Belfast East77093905011,031332,131
BelfastGilnahirk3,481Belfast East8511,03505611,137372,352
BelfastHillfoot1,430Belfast East35862900442438967
BelfastKnock3,520Belfast East8611,04705611,151372,379
BelfastMerok3,010Belfast East74171,3230092511172,034
BelfastOrangefield3,255Belfast East80181,4310099554182,200
BelfastSandown3,092Belfast East75091904911,010332,087
BelfastShandon3,516Belfast East8611,04505611,150372,376
BelfastStormont3,398Belfast East8311,01005511,111362,297
BelfastSydenham3,583Belfast East88201,57500109609202,421
BelfastWoodstock48Belfast East10210018031
Lisburn and CastlereaghBallyhanwood1,914Down North2107270330496161,293
Lisburn and CastlereaghCarrowreagh2,554Down North2809710430661211,724
Lisburn and CastlereaghDundonald2,082Down North2307920360539171,407
Lisburn and CastlereaghEnler2,215Down North2508420370573191,496
Lisburn and CastlereaghGraham's Bridge2,090Down North2307950360541181,413
 Total63,494 1,40816723,920056089315,44450142,893

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
2017
New SeatUUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
BelfastGarnerville219Belfast East0046073614121
North Down and ArdsBallycrochan2,191Down North0053404318581351,211
North Down and ArdsBallygrainey3,420Down North00728013225948571,890
North Down and ArdsBallyholme2,643Down North00562010219732441,459
North Down and ArdsBallymagee2,967Down North0072305924787481,641
North Down and ArdsBloomfield2,899Down North00618011121802491,601
North Down and ArdsBroadway2,618Down North00557010019725441,445
North Down and ArdsBryansburn2,586Down North02958808517670411,430
North Down and ArdsCarrowdore843Strangford03728100331097467
North Down and ArdsCastle2,864Down North00610011021794481,583
North Down and ArdsClandeboye2,646Down North030619020019560341,462
North Down and ArdsCultra2,681Down North030628020319568341,482
North Down and ArdsDonaghadee2,930Down North0071405824777471,620
North Down and ArdsGroomsport2,569Down North0062505121682411,420
North Down and ArdsHarbour3,297Down North00703012624914551,822
North Down and ArdsHelen's Bay2,555Down North029598019318541331,412
North Down and ArdsHolywood3,146Down North036736023823666401,739
North Down and ArdsKilcooley3,013Down North03368509819781471,663
North Down and ArdsLoughries1,157Strangford05138600451509641
North Down and ArdsLoughview3,445Down North039805026125730441,904
North Down and ArdsRathgael2,462Down North02755908116638391,360
North Down and ArdsRathmore2,611Down North02959408517677411,443
North Down and ArdsSilverbirch3,016Down North0073405924800481,665
North Down and ArdsSilverstream2,738Down North03062309018709431,513
North Down and ArdsWarren2,818Down North0068705523747451,557
 Total64,334 040014,94302,54753516,14997735,551

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
2017
Old Seat UUP
Votes
SDLP
Votes
DUP
Votes
UKIP
Votes
Green
Votes
SF
Votes
MIN
Votes
OTH
Votes
Total
Votes
Lisburn and CastlereaghBallyhanwood2,208Belfast East2107270330496161,293
Lisburn and CastlereaghCarrowreagh3,054Belfast East2809710430661211,724
Lisburn and CastlereaghDundonald2,223Belfast East2307920360539171,407
Lisburn and CastlereaghEnler2,156Belfast East2508420370573191,496
Lisburn and CastlereaghGraham's Bridge2,120Belfast East2307950360541181,413
North Down and ArdsBallycrochan2,578Down North0053404318581351,211
North Down and ArdsBallygrainey3,173Down North00728013225948571,890
North Down and ArdsBallyholme2,865Down North00562010219732441,459
North Down and ArdsBallymagee2,968Down North0072305924787481,641
North Down and ArdsBloomfield2,778Down North00618011121802491,601
North Down and ArdsBroadway2,743Down North00557010019725441,445
North Down and ArdsBryansburn2,837Down North02958808517670411,430
North Down and ArdsCastle2,747Down North00610011021794481,583
North Down and ArdsClandeboye2,692Down North030619020019560341,462
North Down and ArdsCultra2,888Down North030628020319568341,482
North Down and ArdsDonaghadee2,864Down North0071405824777471,620
North Down and ArdsGroomsport2,831Down North0062505121682411,420
North Down and ArdsHarbour2,979Down North00703012624914551,822
North Down and ArdsHelen's Bay2,765Down North029598019318541331,412
North Down and ArdsHolywood3,089Down North036736023823666401,739
North Down and ArdsKilcooley2,689Down North03368509819781471,663
North Down and ArdsLoughview2,820Down North039805026125730441,904
North Down and ArdsRathgael2,440Down North02755908116638391,360
North Down and ArdsRathmore2,864Down North02959408517677411,443
North Down and ArdsSilverbirch2,841Down North0073405924800481,665
North Down and ArdsSilverstream2,508Down North03062309018709431,513
North Down and ArdsWarren2,925Down North0068705523747451,557
 Total73,645 12031218,35702,72545418,6391,04841,655

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


© 2017 Martin Baxter
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