Hitchin and Harpenden: New Boundaries 2018 Calculation

Hitchin and Harpenden: Overview

Projection: CON seat

Implied MP at 2017:Bim Afolami  (CON)
County/Area:Hertfordshire (Anglia)
Electorate:75,915
Turnout:77.4%

PartyImplied 2017 VotesImplied 2017 Share
CON31,18953.1%
LAB19,15532.6%
LIB6,23610.6%
Green1,3282.3%
OTH8711.5%
CON Majority12,03420.5%

See overview of other seats in Anglia.



Introduction

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

Hitchin and Harpenden: Map

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

List of old seats forming part of Hitchin and Harpenden

The old seat(s) needed are:

Old seat: Hitchin and Harpenden

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

Old seat: Hitchin and HarpendenTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
North HertfordshireCadwell1,772Hitchin and Harpenden73041511003100111,297
North HertfordshireChesfield5,004Hitchin and Harpenden2,2991,43650907600394,359
North HertfordshireHitchin Bearton5,971Hitchin and Harpenden1,7652,531535014700455,023
North HertfordshireHitchin Highbury5,916Hitchin and Harpenden2,0671,436843013000414,517
North HertfordshireHitchin Oughton3,546Hitchin and Harpenden1,0401,62423208700363,019
North HertfordshireHitchin Priory3,587Hitchin and Harpenden1,50474826207500262,615
North HertfordshireHitchin Walsworth5,829Hitchin and Harpenden2,0092,052430013000404,661
North HertfordshireHitchwood, Offa and Hoo5,586Hitchin and Harpenden2,7301,11129609900444,280
North HertfordshireKimpton1,714Hitchin and Harpenden8543056402800231,274
St AlbansHarpenden East5,314Hitchin and Harpenden2,4681,341550065001234,547
St AlbansHarpenden North5,236Hitchin and Harpenden2,4091,2054370108001084,267
St AlbansHarpenden South5,235Hitchin and Harpenden2,584940375047001164,062
St AlbansHarpenden West5,561Hitchin and Harpenden2,7151,149512065001124,553
St AlbansRedbourn4,746Hitchin and Harpenden2,26098830408400373,673
St AlbansSandridge3,628Hitchin and Harpenden1,61986634407200242,925
St AlbansWheathampstead4,833Hitchin and Harpenden2,1361,00843308400463,707
 Total73,478 31,18919,1556,23601,3280087158,779

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

New seat: Hitchin and Harpenden

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

New seat: Hitchin and Harpenden
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
North HertfordshireCadwell1,674Hitchin and Harpenden73041511003100111,297
North HertfordshireChesfield5,630Hitchin and Harpenden2,2991,43650907600394,359
North HertfordshireHitchin Bearton6,487Hitchin and Harpenden1,7652,531535014700455,023
North HertfordshireHitchin Highbury5,834Hitchin and Harpenden2,0671,436843013000414,517
North HertfordshireHitchin Oughton3,899Hitchin and Harpenden1,0401,62423208700363,019
North HertfordshireHitchin Priory3,377Hitchin and Harpenden1,50474826207500262,615
North HertfordshireHitchin Walsworth6,021Hitchin and Harpenden2,0092,052430013000404,661
North HertfordshireHitchwood, Offa and Hoo5,527Hitchin and Harpenden2,7301,11129609900444,280
North HertfordshireKimpton1,645Hitchin and Harpenden8543056402800231,274
St AlbansHarpenden East5,873Hitchin and Harpenden2,4681,341550065001234,547
St AlbansHarpenden North5,511Hitchin and Harpenden2,4091,2054370108001084,267
St AlbansHarpenden South5,247Hitchin and Harpenden2,584940375047001164,062
St AlbansHarpenden West5,880Hitchin and Harpenden2,7151,149512065001124,553
St AlbansRedbourn4,743Hitchin and Harpenden2,26098830408400373,673
St AlbansSandridge3,779Hitchin and Harpenden1,61986634407200242,925
St AlbansWheathampstead4,788Hitchin and Harpenden2,1361,00843308400463,707
 Total75,915 31,18919,1556,23601,3280087158,779

And these are the implied results for 2017 for the new seat of Hitchin and Harpenden. 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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