New Seat Details - Chingford and Woodford Green

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

Party	Implied 2017 Votes	Implied 2017 Share
CON	25,615	48.3%
LAB	23,902	45.1%
LIB	2,230	4.2%
Green	1,202	2.3%
OTH	38	0.1%
CON Majority	1,713	3.2%

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.

Chingford and Woodford Green: Map

List of old seats forming part of Chingford and Woodford Green

Old seat: Chingford and Woodford Green

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

Old seat: Chingford and Woodford Green				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
Redbridge	Church End	7,855	Chingford and Woodford Green	2,708	2,697	532	0	202	0	0	0	6,139
Redbridge	Monkhams	7,725	Chingford and Woodford Green	3,270	1,831	314	0	137	0	0	0	5,552
Waltham Forest	Chingford Green	7,777	Chingford and Woodford Green	3,201	2,033	166	0	87	0	0	0	5,487
Waltham Forest	Endlebury	8,015	Chingford and Woodford Green	3,138	2,315	138	0	165	0	0	0	5,756
Waltham Forest	Hale End and Highams Park	8,023	Chingford and Woodford Green	2,420	3,051	348	0	194	0	0	0	6,013
Waltham Forest	Hatch Lane	8,063	Chingford and Woodford Green	2,761	2,727	178	0	235	0	0	0	5,901
Waltham Forest	Larkswood	7,919	Chingford and Woodford Green	2,926	2,850	158	0	91	0	0	0	6,025
Waltham Forest	Valley	7,874	Chingford and Woodford Green	2,653	3,134	208	0	91	0	0	0	6,086
	Total	63,251		23,077	20,638	2,042	0	1,202	0	0	0	46,959

The full details of these calculations are given on the Chingford and Woodford Green seat details page. Click on "Show workings".

Old seat: Ilford North

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

Old seat: Ilford North				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
Redbridge	Aldborough	9,277	Ilford North and Wanstead	2,618	4,686	118	0	0	0	0	67	7,489
Redbridge	Barkingside	8,609	Ilford North and Wanstead	2,720	3,705	75	0	0	0	0	19	6,519
Redbridge	Bridge	7,854	Chingford and Woodford Green	2,538	3,264	188	0	0	0	0	38	6,028
Redbridge	Clayhall	9,446	Ilford North and Wanstead	2,772	3,802	120	0	0	0	0	28	6,722
Redbridge	Fairlop	8,328	Ilford North and Wanstead	2,972	3,434	87	0	0	0	0	24	6,517
Redbridge	Fullwell	8,623	Ilford North and Wanstead	2,724	3,867	97	0	0	0	0	80	6,768
Redbridge	Hainault	8,154	Ilford North and Wanstead	2,349	4,160	96	0	0	0	0	80	6,685
Redbridge	Roding	7,689	Ilford North and Wanstead	2,257	3,672	253	0	0	0	0	32	6,214
	Total	67,980		20,950	30,590	1,034	0	0	0	0	368	52,942

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

New seat: Chingford and Woodford Green

District	Ward	Electorate 2017	Old Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
New seat: Chingford and Woodford Green
Redbridge	Bridge	8,313	Ilford North	2,538	3,264	188	0	0	0	0	38	6,028
Redbridge	Church End	8,637	Chingford and Woodford Green	2,708	2,697	532	0	202	0	0	0	6,139
Redbridge	Monkhams	7,812	Chingford and Woodford Green	3,270	1,831	314	0	137	0	0	0	5,552
Waltham Forest	Chingford Green	7,721	Chingford and Woodford Green	3,201	2,033	166	0	87	0	0	0	5,487
Waltham Forest	Endlebury	8,101	Chingford and Woodford Green	3,138	2,315	138	0	165	0	0	0	5,756
Waltham Forest	Hale End and Highams Park	8,461	Chingford and Woodford Green	2,420	3,051	348	0	194	0	0	0	6,013
Waltham Forest	Hatch Lane	8,303	Chingford and Woodford Green	2,761	2,727	178	0	235	0	0	0	5,901
Waltham Forest	Larkswood	8,478	Chingford and Woodford Green	2,926	2,850	158	0	91	0	0	0	6,025
Waltham Forest	Valley	8,564	Chingford and Woodford Green	2,653	3,134	208	0	91	0	0	0	6,086
	Total	74,390		25,615	23,902	2,230	0	1,202	0	0	38	52,987

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

Implied MP at 2017:	Iain Duncan Smith (CON)
County/Area:	Waltham Forest (London)
Electorate:	74,390
Turnout:	71.2%

Chingford and Woodford Green: New Boundaries 2018 Calculation

Chingford and Woodford Green: Overview

Introduction