New Seat Details - Stourbridge

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Stourbridge 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	27,671	54.0%
LAB	19,927	38.9%
UKIP	1,995	3.9%
LIB	1,152	2.2%
Green	541	1.1%
CON Majority	7,744	15.1%

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.

Stourbridge: Map

List of old seats forming part of Stourbridge

Old seat: Dudley South

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

Old seat: Dudley South				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
Dudley	Brierley Hill	9,845	Dudley; Stourbridge	3,202	3,055	113	315	78	0	0	0	6,763
Dudley	Brockmoor and Pensnett	9,585	Dudley	3,013	2,750	81	294	57	0	0	0	6,195
Dudley	Kingswinford North and Wall Heath	10,108	Dudley	4,044	1,561	118	272	60	0	0	0	6,055
Dudley	Kingswinford South	10,272	Dudley	4,150	1,509	98	274	56	0	0	0	6,087
Dudley	Netherton, Woodside and St Andrews	10,352	Halesowen and Rowley Regis	3,468	3,075	96	347	77	0	0	0	7,063
Dudley	Wordsley	10,122	Dudley	3,710	1,908	120	289	54	0	0	0	6,081
	Total	60,284		21,587	13,858	626	1,791	382	0	0	0	38,244

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

Old seat: Stourbridge

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

Old seat: Stourbridge				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
Dudley	Amblecote	10,445	Stourbridge	4,147	2,399	120	279	72	0	0	0	7,017
Dudley	Cradley and Wollescote	9,756	Stourbridge	3,101	3,454	77	269	69	0	0	0	6,970
Dudley	Lye and Stourbridge North	9,264	Stourbridge	3,115	3,023	91	254	71	0	0	0	6,554
Dudley	Norton	9,712	Stourbridge	3,945	1,684	222	219	62	0	0	0	6,132
Dudley	Pedmore and Stourbridge East	9,895	Stourbridge	4,145	1,756	171	223	56	0	0	0	6,351
Dudley	Quarry Bank and Dudley Wood	10,113	Stourbridge	3,369	3,341	104	295	72	0	0	0	7,181
Dudley	Wollaston and Stourbridge Town	10,118	Stourbridge	3,885	2,396	298	263	91	0	0	0	6,933
	Total	69,303		25,707	18,053	1,083	1,802	493	0	0	0	47,138

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

New seat: Stourbridge

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: Stourbridge
Dudley	Amblecote	10,453	Stourbridge	4,147	2,399	120	279	72	0	0	0	7,017
Dudley	Brierley Hill	6,652	Dudley South	1,964	1,874	69	193	48	0	0	0	4,148
Dudley	Cradley and Wollescote	10,381	Stourbridge	3,101	3,454	77	269	69	0	0	0	6,970
Dudley	Lye and Stourbridge North	9,761	Stourbridge	3,115	3,023	91	254	71	0	0	0	6,554
Dudley	Norton	9,135	Stourbridge	3,945	1,684	222	219	62	0	0	0	6,132
Dudley	Pedmore and Stourbridge East	9,460	Stourbridge	4,145	1,756	171	223	56	0	0	0	6,351
Dudley	Quarry Bank and Dudley Wood	10,697	Stourbridge	3,369	3,341	104	295	72	0	0	0	7,181
Dudley	Wollaston and Stourbridge Town	10,328	Stourbridge	3,885	2,396	298	263	91	0	0	0	6,933
	Total	76,867		27,671	19,927	1,152	1,995	541	0	0	0	51,286

And these are the implied results for 2017 for the new seat of Stourbridge. 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:	Margot James (CON)
County/Area:	Black Country (West Midlands)
Electorate:	76,867
Turnout:	66.7%

Stourbridge: New Boundaries 2018 Calculation

Stourbridge: Overview

Introduction