Norwich North: New Boundaries 2018 Calculation

Norwich North: Overview

Projection: LAB seat

Implied MP at 2017:Unknown (changed seat)  (LAB)
County/Area:Norfolk (Anglia)
Electorate:75,845
Turnout:68.7%

PartyImplied 2017 VotesImplied 2017 Share
LAB25,47148.9%
CON23,57845.3%
LIB1,7093.3%
Green9711.9%
OTH3410.7%
LAB Majority1,8933.6%

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 Norwich North 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.

Norwich North: Map

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

List of old seats forming part of Norwich North

The old seat(s) needed are:

Old seat: Norwich North

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

Old seat: Norwich NorthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
BroadlandHellesdon North West4,539Norwich North1,8281,0959802500203,066
BroadlandHellesdon South East3,894Norwich North1,5251,0139602300242,681
BroadlandOld Catton and Sprowston West6,338Norwich North2,5541,66515003800254,432
BroadlandSprowston Central4,150Norwich North1,4761,2629802600162,878
BroadlandSprowston East5,617Norwich North1,9971,41913103300213,601
BroadlandThorpe St Andrew North West5,635Norwich North2,1021,53514503600233,841
BroadlandThorpe St Andrew South East5,074Norwich North2,2841,34013203800213,815
NorwichCatton Grove7,267Norwich North2,2622,926150013700435,518
NorwichCrome6,943Norwich North2,0142,899126012500595,223
NorwichMile Cross6,939Norwich North1,9393,319150014500535,606
NorwichSewell7,091Norwich North1,9192,919203015600365,233
 Total63,487 21,90021,3921,47907820034145,894

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

Old seat: Norwich South

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

Old seat: Norwich SouthTransfer-adjusted Results
DistrictWardElectorate
2017
New SeatCON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
NorwichBowthorpe7,872Norwich South1,9333,85726101570006,208
NorwichEaton7,167Norwich South1,9232,29232501260004,666
NorwichLakenham6,709Norwich South1,3223,19232801360004,978
NorwichMancroft7,466Norwich South1,4123,29424801640005,118
NorwichNelson6,650Norwich South1,3443,08235301960004,975
NorwichThorpe Hamlet8,199Norwich South1,9113,18329501600005,549
NorwichTown Close7,968Norwich South1,8103,16536401770005,516
NorwichUniversity5,101Norwich South1,3303,65925201540005,395
NorwichWensum7,705Norwich North1,6784,07923001890006,176
South NorfolkNew Costessey4,126Norwich South1,0521,5081850330002,778
 Total68,963 15,71531,3112,84101,49200051,359

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

New seat: Norwich North

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

New seat: Norwich North
DistrictWardElectorate
2017
Old Seat CON
Votes
LAB
Votes
LIB
Votes
UKIP
Votes
Green
Votes
NAT
Votes
MIN
Votes
OTH
Votes
Total
Votes
BroadlandHellesdon North West4,472Norwich North1,8281,0959802500203,066
BroadlandHellesdon South East3,909Norwich North1,5251,0139602300242,681
BroadlandOld Catton and Sprowston West6,463Norwich North2,5541,66515003800254,432
BroadlandSprowston Central4,197Norwich North1,4761,2629802600162,878
BroadlandSprowston East5,250Norwich North1,9971,41913103300213,601
BroadlandThorpe St Andrew North West5,600Norwich North2,1021,53514503600233,841
BroadlandThorpe St Andrew South East5,562Norwich North2,2841,34013203800213,815
NorwichCatton Grove8,048Norwich North2,2622,926150013700435,518
NorwichCrome7,616Norwich North2,0142,899126012500595,223
NorwichMile Cross8,175Norwich North1,9393,319150014500535,606
NorwichSewell7,633Norwich North1,9192,919203015600365,233
NorwichWensum8,920Norwich South1,6784,07923001890006,176
 Total75,845 23,57825,4711,70909710034152,070

And these are the implied results for 2017 for the new seat of Norwich North. Please note that the wards used are those of 2015 in order to be consistent with those used by the Boundary Commissions.


© 2024 Electoral Calculus Ltd
Powered by TigerLib (14-Mar-2024 12:19, Py3L, sc706)