Rossendale and Darwen: New Boundaries 2018 Calculation

Rossendale and Darwen: Overview

Projection: CON seat

Implied MP at 2017:Jake Berry  (CON)
County/Area:Lancashire (North West)
Electorate:77,336
Turnout:68.3%

PartyImplied 2017 VotesImplied 2017 Share
CON26,26449.7%
LAB23,94145.3%
LIB1,5933.0%
Green7971.5%
UKIP2290.4%
CON Majority2,3234.4%

See overview of other seats in North West.



Introduction

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

Rossendale and Darwen: Map

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

List of old seats forming part of Rossendale and Darwen

The old seat(s) needed are:

Old seat: Hyndburn

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

Old seat: HyndburnTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
HyndburnAltham3,982Hyndburn1,0441,4705312300002,690
HyndburnBarnfield3,233Hyndburn8791,199419500002,214
HyndburnBaxenden3,333Hyndburn1,021785458600001,937
HyndburnCentral3,596Hyndburn7272,106298000002,942
HyndburnChurch3,260Hyndburn6371,537329800002,304
HyndburnClayton-le-Moors3,547Hyndburn1,0141,1454410300002,306
HyndburnHuncoat3,569Hyndburn9211,057399700002,114
HyndburnImmanuel3,508Hyndburn1,1181,0004510300002,266
HyndburnMilnshaw3,485Hyndburn7511,251459300002,140
HyndburnNetherton3,239Hyndburn9311,147399800002,215
HyndburnOverton4,964Hyndburn1,2441,6096215500003,070
HyndburnPeel2,999Hyndburn6441,4764510000002,265
HyndburnRishton5,093Hyndburn1,3811,6565415100003,242
HyndburnSpring Hill3,474Hyndburn8481,589329900002,568
HyndburnSt Andrew's3,357Hyndburn1,049932459500002,121
HyndburnSt Oswald's5,076Hyndburn1,5181,3666615000003,100
RossendaleGreenfield4,325Rossendale and Darwen1,4611,1554911300002,778
RossendaleWorsley4,053Rossendale and Darwen1,1151,6415811600002,930
 Total68,093 18,30324,1218231,955000045,202

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

Old seat: Rossendale and Darwen

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

Old seat: Rossendale and DarwenTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Blackburn with DarwenEarcroft2,943Rossendale and Darwen9791,196910210002,287
Blackburn with DarwenEast Rural1,462Rossendale and Darwen6533161809000996
Blackburn with DarwenFernhurst4,125Blackburn1,8101,141630260003,040
Blackburn with DarwenMarsh House4,442Rossendale and Darwen1,6791,4811700340003,364
Blackburn with DarwenNorth Turton with Tockholes3,466Rossendale and Darwen1,496694330220002,245
Blackburn with DarwenSudell4,343Rossendale and Darwen1,4811,8991840360003,600
Blackburn with DarwenSunnyhurst4,295Rossendale and Darwen1,4171,6171230340003,191
Blackburn with DarwenWhitehall2,964Rossendale and Darwen1,1148471580260002,145
RossendaleCribden2,751Rossendale and Darwen1,048821420560001,967
RossendaleEden2,864Rossendale and Darwen1,158581340500001,823
RossendaleFacit and Shawforth2,741Rossendale and Darwen958821360210001,836
RossendaleGoodshaw3,159Rossendale and Darwen9921,054540240002,124
RossendaleGreensclough4,274Rossendale and Darwen1,5351,372620340003,003
RossendaleHareholme4,050Rossendale and Darwen1,3171,336670350002,755
RossendaleHealey and Whitworth2,992Rossendale and Darwen9901,010410270002,068
RossendaleHelmshore4,776Rossendale and Darwen1,8761,040650850003,066
RossendaleIrwell4,013Rossendale and Darwen1,3801,342510790002,852
RossendaleLongholme4,083Rossendale and Darwen1,4041,310540860002,854
RossendaleStacksteads2,802Rossendale and Darwen8051,114430250001,987
RossendaleWhitewell4,193Rossendale and Darwen1,4061,2941600930002,953
 Total70,738 25,49822,2861,549082300050,156

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

New seat: Rossendale and Darwen

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

New seat: Rossendale and Darwen
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Blackburn with DarwenEarcroft3,305Rossendale and Darwen9791,196910210002,287
Blackburn with DarwenEast Rural1,439Rossendale and Darwen6533161809000996
Blackburn with DarwenMarsh House4,862Rossendale and Darwen1,6791,4811700340003,364
Blackburn with DarwenNorth Turton with Tockholes3,246Rossendale and Darwen1,496694330220002,245
Blackburn with DarwenSudell5,203Rossendale and Darwen1,4811,8991840360003,600
Blackburn with DarwenSunnyhurst4,613Rossendale and Darwen1,4171,6171230340003,191
Blackburn with DarwenWhitehall3,100Rossendale and Darwen1,1148471580260002,145
RossendaleCribden2,843Rossendale and Darwen1,048821420560001,967
RossendaleEden2,634Rossendale and Darwen1,158581340500001,823
RossendaleFacit and Shawforth2,654Rossendale and Darwen958821360210001,836
RossendaleGoodshaw3,070Rossendale and Darwen9921,054540240002,124
RossendaleGreenfield4,495Hyndburn1,4611,1554911300002,778
RossendaleGreensclough4,341Rossendale and Darwen1,5351,372620340003,003
RossendaleHareholme3,982Rossendale and Darwen1,3171,336670350002,755
RossendaleHealey and Whitworth2,989Rossendale and Darwen9901,010410270002,068
RossendaleHelmshore4,431Rossendale and Darwen1,8761,040650850003,066
RossendaleIrwell4,122Rossendale and Darwen1,3801,342510790002,852
RossendaleLongholme4,125Rossendale and Darwen1,4041,310540860002,854
RossendaleStacksteads2,873Rossendale and Darwen8051,114430250001,987
RossendaleWhitewell4,269Rossendale and Darwen1,4061,2941600930002,953
RossendaleWorsley4,740Hyndburn1,1151,6415811600002,930
 Total77,336 26,26423,9411,59322979700052,824

And these are the implied results for 2017 for the new seat of Rossendale and Darwen. 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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