Ruislip, Northwood and Pinner: New Boundaries 2018 Calculation

Ruislip, Northwood and Pinner: Overview

 Projection: CON seat 

Implied MP at 2017: Nick Hurd  (CON)
County/Area: Hillingdon (London)
Electorate: 71,331
Turnout: 74.8%

 Implied 2017 VotesImplied 2017 Share
CON Majority13,97926.2%

See overview of other seats in London.

Ruislip, Northwood and Pinner : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Ruislip, Northwood and Pinner constituency, the 'London' 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.

IndicatorSeatLondonAll GB
Economic Position27° Right11° Right
National Position17° Int29° Int1° Int
EU Leave %49%40%52%
British Identity24%38%29%
Good Health44%50%48%
UK Born90%64%88%
Good Education31%48%39%
Good Job51%61%51%
High SEC49%55%51%
Average Age48.744.148.5
ABC1 Class51%62%53%

Ruislip, Northwood and Pinner ranks #405 for "Leave", #5 for "Right" and #518 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:

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

Ruislip, Northwood and Pinner: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015


This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Ruislip, Northwood and Pinner 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 Ruislip, Northwood and Pinner

The old seat(s) needed are:

Old seat: Ruislip, Northwood and Pinner

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

Old seat: Ruislip, Northwood and PinnerTransfer-adjusted Results
New SeatCON
HarrowHatch End8,368Ruislip, Northwood and Pinner3,6012,10127465430006,084
HarrowPinner7,725Ruislip, Northwood and Pinner3,1511,871393511510005,617
HarrowPinner South8,105Ruislip, Northwood and Pinner3,1832,24134054750005,893
HillingdonEastcote and East Ruislip9,602Ruislip, Northwood and Pinner4,3991,6495681681960006,980
HillingdonHarefield5,831Ruislip, Northwood and Pinner1,9031,5773642781170004,239
HillingdonIckenham8,160Ruislip, Northwood and Pinner3,7891,4983521651290005,933
HillingdonNorthwood8,220Ruislip, Northwood and Pinner3,8561,405452661970005,976
HillingdonNorthwood Hills9,096Ruislip, Northwood and Pinner3,1612,6105681181550006,612
HillingdonWest Ruislip8,318Ruislip, Northwood and Pinner3,5111,6235042052040006,047
 Total73,425 30,55416,5753,8151,1701,26700053,381

The full details of these calculations are given on the Ruislip, Northwood and Pinner seat details page. Click on "Show workings".

New seat: Ruislip, Northwood and Pinner

The new seat of Ruislip, Northwood and Pinner is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Ruislip, Northwood and Pinner
Old Seat CON
HarrowHatch End8,207Ruislip, Northwood and Pinner3,6012,10127465430006,084
HarrowPinner7,825Ruislip, Northwood and Pinner3,1511,871393511510005,617
HarrowPinner South7,802Ruislip, Northwood and Pinner3,1832,24134054750005,893
HillingdonEastcote and East Ruislip9,701Ruislip, Northwood and Pinner4,3991,6495681681960006,980
HillingdonHarefield5,350Ruislip, Northwood and Pinner1,9031,5773642781170004,239
HillingdonIckenham7,945Ruislip, Northwood and Pinner3,7891,4983521651290005,933
HillingdonNorthwood7,863Ruislip, Northwood and Pinner3,8561,405452661970005,976
HillingdonNorthwood Hills8,306Ruislip, Northwood and Pinner3,1612,6105681181550006,612
HillingdonWest Ruislip8,332Ruislip, Northwood and Pinner3,5111,6235042052040006,047
 Total71,331 30,55416,5753,8151,1701,26700053,381

And these are the implied results for 2017 for the new seat of Ruislip, Northwood and Pinner.

© 2018 Martin Baxter
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