Perth and North Perthshire: New Boundaries 2018 Calculation

Perth and North Perthshire: Overview

 Projection: SNP seat 

Implied MP at 2017: Pete Wishart  (SNP)
County/Area: Tayside (Scotland)
Electorate: 72,831
Turnout: 73.4%

 Implied 2017 VotesImplied 2017 Share
SNP22,62942.3%
CON22,61742.3%
LAB5,50110.3%
LIB2,6995.0%
SNP Majority120.0%

See overview of other seats in Scotland.

Perth and North Perthshire : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Perth and North Perthshire constituency, the 'Scotland' 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.

IndicatorSeatScotlandAll GB
Party WinnerSNPSNPCON
Economic Position3° Left14° Left
National Position12° Int17° Int1° Int
EU Leave %39%38%52%
British Identity34%27%29%
Good Health55%52%48%
UK Born72%93%88%
Good Education59%36%39%
Good Job59%49%51%
High SEC52%55%51%
Average Age40.348.748.5
ABC1 Class63%50%53%

Perth and North Perthshire ranks #524 for "Leave", #386 for "Right" and #477 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

Perth and North Perthshire: 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 Perth and North Perthshire 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 Perth and North Perthshire

The old seat(s) needed are:

Old seat: Ochil and South Perthshire

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

Old seat: Ochil and South PerthshireTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
SNP
Votes
MIN
Votes
OTH
Votes
Total
Votes
ClackmannanshireClackmannanshire Central6,302Clackmannanshire and Dunfermline1,0781,61311001,744004,446
ClackmannanshireClackmannanshire East5,580Clackmannanshire and Dunfermline1,75285378001,254003,937
ClackmannanshireClackmannanshire North8,334Clackmannanshire and Dunfermline2,0211,419125002,316005,881
ClackmannanshireClackmannanshire South9,558Clackmannanshire and Dunfermline1,7082,03118002,987006,744
ClackmannanshireClackmannanshire West9,591Clackmannanshire and Dunfermline1,8022,4572002,506006,767
Perth and KinrossAlmond and Earn8,927Stirlingshire and South Perthshire3,344673175002,107006,299
Perth and KinrossKinross-shire9,691Stirlingshire and South Perthshire3,986659399001,794006,838
Perth and KinrossStrathallan7,641Stirlingshire and South Perthshire2,631476470001,814005,391
Perth and KinrossStrathearn8,421Stirlingshire and South Perthshire3,312511356001,762005,941
Perth and KinrossStrathtay2,724Perth and North Perthshire83515310900825001,922
 Total76,769 22,46910,8451,7430019,1090054,166

The full details of these calculations are given on the Ochil and South Perthshire seat details page. Click on "Show workings".

Old seat: Perth and North Perthshire

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

Old seat: Perth and North PerthshireTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
SNP
Votes
MIN
Votes
OTH
Votes
Total
Votes
Perth and KinrossBlairgowrie and Glens8,093Perth and North Perthshire2,409294337002,773005,813
Perth and KinrossCarse of Gowrie7,199Perth and North Perthshire2,24953481002,306005,170
Perth and KinrossHighland6,798Perth and North Perthshire2,263111396002,111004,881
Perth and KinrossPerth City Centre11,591Perth and North Perthshire3,5321,045415003,333008,325
Perth and KinrossPerth City North12,537Perth and North Perthshire2,6152,13498004,156009,003
Perth and KinrossPerth City South10,416Perth and North Perthshire3,858712510002,401007,481
Perth and KinrossStrathmore10,876Perth and North Perthshire3,608376550003,276007,810
Perth and KinrossStrathtay4,232Perth and North Perthshire1,248142203001,448003,041
 Total71,742 21,7825,3482,5900021,8040051,524

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

New seat: Perth and North Perthshire

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

New seat: Perth and North Perthshire
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
SNP
Votes
MIN
Votes
OTH
Votes
Total
Votes
Perth and KinrossBlairgowrie and Glens8,171Perth and North Perthshire2,409294337002,773005,813
Perth and KinrossCarse of Gowrie7,506Perth and North Perthshire2,24953481002,306005,170
Perth and KinrossHighland6,815Perth and North Perthshire2,263111396002,111004,881
Perth and KinrossPerth City Centre10,092Perth and North Perthshire3,5321,045415003,333008,325
Perth and KinrossPerth City North10,831Perth and North Perthshire2,6152,13498004,156009,003
Perth and KinrossPerth City South10,747Perth and North Perthshire3,858712510002,401007,481
Perth and KinrossStrathmore11,518Perth and North Perthshire3,608376550003,276007,810
Perth and KinrossStrathtay2,800Ochil and South Perthshire81611612200890001,944
Perth and KinrossStrathtay4,351Perth and North Perthshire1,267179190001,383003,019
 Total72,831 22,6175,5012,6990022,6290053,446

And these are the implied results for 2017 for the new seat of Perth and North Perthshire.


© 2017 Martin Baxter
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