New Seat Details - West Bromwich

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for West Bromwich 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
LAB	30,354	60.9%
CON	17,532	35.2%
LIB	832	1.7%
Green	664	1.3%
OTH	316	0.6%
MIN	99	0.2%
UKIP	55	0.1%
LAB Majority	12,822	25.7%

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.

West Bromwich: Map

List of old seats forming part of West Bromwich

Old seat: Birmingham Perry Barr

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

Old seat: Birmingham Perry Barr				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
Birmingham	Handsworth Wood	17,301	West Bromwich	2,994	7,878	206	0	147	0	99	17	11,341
Birmingham	Lozells and East Handsworth	17,558	Birmingham Ladywood	1,938	10,311	196	0	170	0	276	46	12,937
Birmingham	Oscott	17,483	Walsall and Oscott	3,924	5,737	250	0	130	0	121	20	10,182
Birmingham	Perry Barr	15,368	Birmingham Erdington and Perry Barr	2,871	6,182	428	0	143	0	96	16	9,736
	Total	67,710		11,727	30,108	1,080	0	590	0	592	99	44,196

The full details of these calculations are given on the Birmingham Perry Barr seat details page. Click on "Show workings".

Old seat: Warley

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

Old seat: Warley				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
Sandwell	Abbey	7,865	Warley	1,517	3,155	169	184	93	0	0	0	5,118
Sandwell	Bristnall	8,851	Warley	1,738	3,158	98	215	77	0	0	0	5,286
Sandwell	Langley	8,958	Warley	1,754	3,379	96	219	75	0	0	0	5,523
Sandwell	Old Warley	8,965	Warley	2,018	2,679	192	196	76	0	0	0	5,161
Sandwell	Smethwick	9,014	Warley	1,268	4,338	84	205	78	0	0	0	5,973
Sandwell	Soho and Victoria	8,733	Birmingham Ladywood	1,091	5,427	66	153	84	0	0	0	6,821
Sandwell	St Pauls	8,960	Warley; West Bromwich	1,134	4,868	72	177	73	0	0	0	6,324
	Total	61,346		10,520	27,004	777	1,349	556	0	0	0	40,206

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

Old seat: West Bromwich East

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

Old seat: West Bromwich East				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
Sandwell	Charlemont with Grove Vale	9,132	West Bromwich	2,649	2,489	69	0	98	0	0	57	5,362
Sandwell	Friar Park	8,741	West Bromwich	2,042	3,400	58	0	44	0	0	38	5,582
Sandwell	Great Barr with Yew Tree	9,438	West Bromwich	2,482	2,745	247	0	73	0	0	40	5,587
Sandwell	Greets Green and Lyng	8,042	Darlaston and Tipton; West Bromwich	1,582	3,510	45	0	82	0	0	55	5,274
Sandwell	Hateley Heath	9,379	West Bromwich	2,123	3,926	57	0	93	0	0	45	6,244
Sandwell	Newton	8,544	West Bromwich	2,321	2,640	89	0	48	0	0	39	5,137
Sandwell	West Bromwich Central	8,757	West Bromwich	1,751	3,955	60	0	96	0	0	51	5,913
	Total	62,033		14,950	22,665	625	0	534	0	0	325	39,099

The full details of these calculations are given on the West Bromwich East seat details page. Click on "Show workings".

New seat: West Bromwich

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: West Bromwich
Birmingham	Handsworth Wood	17,990	Birmingham Perry Barr	2,994	7,878	206	0	147	0	99	17	11,341
Sandwell	Charlemont with Grove Vale	8,754	West Bromwich East	2,649	2,489	69	0	98	0	0	57	5,362
Sandwell	Friar Park	9,113	West Bromwich East	2,042	3,400	58	0	44	0	0	38	5,582
Sandwell	Great Barr with Yew Tree	9,119	West Bromwich East	2,482	2,745	247	0	73	0	0	40	5,587
Sandwell	Greets Green and Lyng	4,466	West Bromwich East	821	1,820	23	0	43	0	0	29	2,736
Sandwell	Hateley Heath	10,197	West Bromwich East	2,123	3,926	57	0	93	0	0	45	6,244
Sandwell	Newton	8,386	West Bromwich East	2,321	2,640	89	0	48	0	0	39	5,137
Sandwell	St Pauls	3,089	Warley	350	1,501	22	55	23	0	0	0	1,951
Sandwell	West Bromwich Central	9,653	West Bromwich East	1,751	3,955	60	0	96	0	0	51	5,913
	Total	80,767		17,533	30,354	831	55	665	0	99	316	49,853

And these are the implied results for 2017 for the new seat of West Bromwich. 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:	Tom Watson (LAB)
County/Area:	Black Country (West Midlands)
Electorate:	80,767
Turnout:	61.7%

West Bromwich: New Boundaries 2018 Calculation

West Bromwich: Overview

Introduction