Blackburn: New Boundaries 2018 Calculation

Blackburn: Overview

 Projection: LAB seat 

Implied MP at 2017: Kate Hollern  (LAB)
County/Area: Lancashire (North West)
Electorate: 72,816
Turnout: 69.4%

 Implied 2017 VotesImplied 2017 Share
LAB34,28967.8%
CON14,61728.9%
MIN8751.7%
LIB7551.5%
Green190.0%
LAB Majority19,67238.9%

See overview of other seats in North West.

Blackburn : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Blackburn constituency, the 'North West' area and nation.

The political measures include the Left/Right and International/National axes (what does this mean).

The demographic measures are from the 2011 Census and include categories relating to national identity, economic activity, health and education. These categories are those which have the most relevance to political attitudes.

IndicatorSeatNorth WestAll GB
Party WinnerLABLABCON
Economic Position5° Left6° Left
National Position3° Nat2° Nat1° Int
EU Leave %57%54%52%
British Identity25%28%29%
Good Health41%46%48%
UK Born96%92%88%
Good Education30%37%39%
Good Job48%49%51%
High SEC46%48%51%
Average Age52.748.648.5
ABC1 Class47%50%53%

Blackburn ranks #220 for "Leave", #427 for "Right" and #272 for "National" out of 600 new seats.

Indicators: Legend and Descriptions

Indicators : Legend and Descriptions

The colour scheme used in the table above is explained in the legend table below. The eight census indicators (British Identity, Good Health, UK Born, Good Education, Good Job, High SEC, Average Age and AB1 Class) all use the same 'Census' colour scheme indicating whether the area's level is above or below the national average.

TopicCat 1Cat 2Cat 3Cat 4Cat 5
Economic PositionVery LeftLeftCentristRightVery Right
National PositionVery IntInternationalCentristNationalVery Nat
EU Leave %Very RemainRemainBalancedLeaveVery Leave
CensusVery LowLowMediumHighVery High

Indicator definitions are given in terms of political data definitions or census categories:

IndicatorCensus
Question
Definition / Included Census Categories
Party WinnerArea party winner : actual election result or projected by Electoral Calculus
Economic PositionEconomic position between 100° Left and 100° Right, estimated by Electoral Calculus from political and demographic data.
National PositionNational position between 100° International and 100° National, estimated by Electoral Calculus from political and demographic data.
EU Leave %EU Referendum vote share for 'Leave' : actual result or estimate
British IdentityNational Identity (KS202)Those answering British, British-Other, or Scottish-British
Good HealthHealth (KS301)Those answering 'Very Good Health'
UK BornCountry of Birth (QS203)Those answering England, Northern Ireland, Scotland, Wales, GB Other, or UK Other
Good EducationHighest level of Qualification (QS501)Level 3 (A-level equivalent) or Level 4+ (degree equivalent)
Good JobOccupation (QS606)Occupation codes 1xx to 4xx (Managers, Professionals, Associates, and office workers)
High SECNS-SeC of Household Reference Person (QS609)National Statistics Socio-economic Classification from 1 to 4 (higher managers and professionals, lower managers and professionals, intermediate occupations, small employers and self-employed).
Average AgeAge (QS103)Average age of adults (18 years and above)
ABC1 ClassApproximated Social Grade (QS611)Approximated social grades A, B and C1

Blackburn: 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 Blackburn 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 Blackburn

The old seat(s) needed are:

Old seat: Blackburn

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

Old seat: BlackburnTransfer-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 DarwenAudley5,922Blackburn7923,085360007003,983
Blackburn with DarwenBastwell5,185Blackburn4222,965260007303,486
Blackburn with DarwenBeardwood with Lammack3,986Blackburn1,4981,102400004102,681
Blackburn with DarwenCorporation Park4,822Blackburn6582,488440005203,242
Blackburn with DarwenEwood4,606Blackburn9132,120350002903,097
Blackburn with DarwenHigher Croft5,184Blackburn8372,4627600011203,487
Blackburn with DarwenLittle Harwood4,505Blackburn7122,208450006503,030
Blackburn with DarwenLivesey with Pleasington4,376Blackburn1,6581,183710003102,943
Blackburn with DarwenMeadowhead3,864Blackburn9771,559330002902,598
Blackburn with DarwenMill Hill4,205Blackburn5552,0721160008502,828
Blackburn with DarwenQueen's Park4,392Blackburn6352,28770002402,953
Blackburn with DarwenRoe Lee4,055Blackburn8971,686720007302,728
Blackburn with DarwenShadsworth with Whitebirk5,629Blackburn5863,0285900011203,785
Blackburn with DarwenShear Brow5,074Blackburn9682,39580004103,412
Blackburn with DarwenWensley Fold4,852Blackburn6742,510410003803,263
 Total70,657 12,78233,150709000875047,516

The full details of these calculations are given on the Blackburn 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 DarwenEarcroft3,305Rossendale and Darwen1,0011,220440210002,286
Blackburn with DarwenEast Rural1,439Rossendale and Darwen658327703000995
Blackburn with DarwenFernhurst4,394Blackburn1,8351,139460190003,039
Blackburn with DarwenMarsh House4,862Rossendale and Darwen1,6861,5581050140003,363
Blackburn with DarwenNorth Turton with Tockholes3,246Rossendale and Darwen1,496705270180002,246
Blackburn with DarwenSudell5,203Rossendale and Darwen1,3931,8703180180003,599
Blackburn with DarwenSunnyhurst4,613Rossendale and Darwen1,3931,6691190110003,192
Blackburn with DarwenWhitehall3,100Rossendale and Darwen1,073773291080002,145
RossendaleCribden2,843Rossendale and Darwen1,024829480650001,966
RossendaleEden2,634Rossendale and Darwen1,0605874801280001,823
RossendaleFacit and Shawforth2,654Rossendale and Darwen966799550150001,835
RossendaleGoodshaw3,070Rossendale and Darwen1,063987530210002,124
RossendaleGreensclough4,341Rossendale and Darwen1,5851,344220520003,003
RossendaleHareholme3,982Rossendale and Darwen1,3261,337790130002,755
RossendaleHealey and Whitworth2,989Rossendale and Darwen1,057966300150002,068
RossendaleHelmshore4,431Rossendale and Darwen1,8251,096460990003,066
RossendaleIrwell4,122Rossendale and Darwen1,4071,37280630002,850
RossendaleLongholme4,125Rossendale and Darwen1,4181,2705801080002,854
RossendaleStacksteads2,873Rossendale and Darwen8371,123150130001,988
RossendaleWhitewell4,269Rossendale and Darwen1,3941,31012901200002,953
 Total72,495 25,49722,2811,548082400050,150

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

New seat: Blackburn

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

New seat: Blackburn
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
Blackburn with DarwenAudley5,595Blackburn7923,085360007003,983
Blackburn with DarwenBastwell4,883Blackburn4222,965260007303,486
Blackburn with DarwenBeardwood with Lammack4,445Blackburn1,4981,102400004102,681
Blackburn with DarwenCorporation Park4,666Blackburn6582,488440005203,242
Blackburn with DarwenEwood4,360Blackburn9132,120350002903,097
Blackburn with DarwenFernhurst4,125Rossendale and Darwen1,8351,139460190003,039
Blackburn with DarwenHigher Croft4,818Blackburn8372,4627600011203,487
Blackburn with DarwenLittle Harwood4,511Blackburn7122,208450006503,030
Blackburn with DarwenLivesey with Pleasington5,289Blackburn1,6581,183710003102,943
Blackburn with DarwenMeadowhead4,107Blackburn9771,559330002902,598
Blackburn with DarwenMill Hill3,721Blackburn5552,0721160008502,828
Blackburn with DarwenQueen's Park3,918Blackburn6352,28770002402,953
Blackburn with DarwenRoe Lee4,450Blackburn8971,686720007302,728
Blackburn with DarwenShadsworth with Whitebirk4,792Blackburn5863,0285900011203,785
Blackburn with DarwenShear Brow4,962Blackburn9682,39580004103,412
Blackburn with DarwenWensley Fold4,174Blackburn6742,510410003803,263
 Total72,816 14,61734,2897550190875050,555

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


© 2017 Martin Baxter
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