New Seat Details - Redditch

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Redditch 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	30,759	55.5%
LAB	18,896	34.1%
MIN	1,960	3.5%
LIB	1,761	3.2%
UKIP	1,301	2.3%
Green	651	1.2%
OTH	87	0.2%
CON Majority	11,863	21.4%

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.

Redditch: Map

List of old seats forming part of Redditch

Old seat: Bromsgrove

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

Old seat: Bromsgrove				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
Bromsgrove	Alvechurch South	2,248	Redditch	1,279	305	55	0	21	0	0	0	1,660
Bromsgrove	Alvechurch Village	2,234	Redditch	972	385	76	0	77	0	0	0	1,510
Bromsgrove	Aston Fields	2,492	Bromsgrove and Droitwich	1,086	675	95	0	78	0	0	0	1,934
Bromsgrove	Avoncroft	2,424	Bromsgrove and Droitwich	1,128	511	63	0	24	0	0	0	1,726
Bromsgrove	Barnt Green and Hopwood	2,208	Redditch	1,203	382	71	0	27	0	0	0	1,683
Bromsgrove	Belbroughton and Romsley	5,193	Bromsgrove and Droitwich	2,931	708	109	0	47	0	0	0	3,795
Bromsgrove	Bromsgrove Central	2,363	Bromsgrove and Droitwich	1,115	663	94	0	32	0	0	0	1,904
Bromsgrove	Catshill North	2,208	Bromsgrove and Droitwich	901	684	77	0	68	0	0	0	1,730
Bromsgrove	Catshill South	2,174	Bromsgrove and Droitwich	926	614	61	0	22	0	0	0	1,623
Bromsgrove	Charford	2,318	Bromsgrove and Droitwich	878	995	79	0	30	0	0	0	1,982
Bromsgrove	Cofton	2,142	Redditch	944	353	55	0	57	0	0	0	1,409
Bromsgrove	Drakes Cross	2,489	Redditch	1,233	466	70	0	27	0	0	0	1,796
Bromsgrove	Hagley East	2,044	Bromsgrove and Droitwich	1,121	355	64	0	25	0	0	0	1,565
Bromsgrove	Hagley West	2,680	Bromsgrove and Droitwich	1,427	482	88	0	33	0	0	0	2,030
Bromsgrove	Hill Top	1,778	Bromsgrove and Droitwich	642	635	62	0	20	0	0	0	1,359
Bromsgrove	Hollywood	2,390	Redditch	1,253	418	67	0	24	0	0	0	1,762
Bromsgrove	Lickey Hills	2,242	Bromsgrove and Droitwich	1,139	275	150	0	19	0	0	0	1,583
Bromsgrove	Lowes Hill	2,565	Bromsgrove and Droitwich	1,102	771	85	0	30	0	0	0	1,988
Bromsgrove	Marlbrook	2,395	Bromsgrove and Droitwich	1,147	433	64	0	66	0	0	0	1,710
Bromsgrove	Norton	2,058	Bromsgrove and Droitwich	985	447	67	0	57	0	0	0	1,556
Bromsgrove	Perryfields	1,385	Bromsgrove and Droitwich	517	255	28	0	12	0	0	0	812
Bromsgrove	Rock Hill	2,414	Bromsgrove and Droitwich	893	847	157	0	28	0	0	0	1,925
Bromsgrove	Rubery North	2,507	Birmingham Northfield	840	852	82	0	28	0	0	0	1,802
Bromsgrove	Rubery South	2,563	Birmingham Northfield	923	842	72	0	28	0	0	0	1,865
Bromsgrove	Sanders Park	2,671	Bromsgrove and Droitwich	987	904	81	0	28	0	0	0	2,000
Bromsgrove	Sidemoor	2,530	Bromsgrove and Droitwich	868	957	88	0	31	0	0	0	1,944
Bromsgrove	Slideslow	2,635	Bromsgrove and Droitwich	1,412	530	147	0	75	0	0	0	2,164
Bromsgrove	Tardebigge	2,209	Bromsgrove and Droitwich	1,476	417	71	0	80	0	0	0	2,044
Bromsgrove	Wythall East	2,344	Redditch	1,147	404	68	0	24	0	0	0	1,643
Bromsgrove	Wythall West	2,139	Redditch	1,019	354	141	0	21	0	0	0	1,535
	Total	72,042		33,494	16,919	2,487	0	1,139	0	0	0	54,039

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

Old seat: Redditch

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

Old seat: Redditch				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
Redditch	Abbey	4,213	Redditch	1,495	1,137	103	89	26	0	149	6	3,005
Redditch	Astwood Bank and Feckenham	4,596	Redditch	1,969	759	34	85	22	0	126	6	3,001
Redditch	Batchley and Brockhill	5,677	Redditch	2,004	1,747	55	131	32	0	177	8	4,154
Redditch	Central	4,015	Redditch	1,324	1,531	76	52	29	0	244	11	3,267
Redditch	Church Hill	5,654	Redditch	1,896	1,737	123	139	37	0	161	7	4,100
Redditch	Crabbs Cross	4,431	Redditch	1,842	780	86	93	25	0	132	6	2,964
Redditch	Greenlands	5,970	Redditch	1,960	1,968	151	150	44	0	218	10	4,501
Redditch	Headless Cross and Oakenshaw	6,588	Redditch	2,511	1,446	141	144	39	0	191	8	4,480
Redditch	Lodge Park	3,633	Redditch	1,179	1,351	78	90	26	0	131	6	2,861
Redditch	Matchborough	4,338	Redditch	1,614	1,077	107	99	30	0	134	6	3,067
Redditch	West	4,360	Redditch	1,775	721	48	84	24	0	113	5	2,770
Redditch	Winyates	6,020	Redditch	2,140	1,575	156	145	39	0	184	8	4,247
Wychavon	Inkberrow	4,576	Evesham	1,943	458	16	70	7	0	281	12	2,787
	Total	64,071		23,652	16,287	1,174	1,371	380	0	2,241	99	45,204

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

New seat: Redditch

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: Redditch
Bromsgrove	Alvechurch South	2,260	Bromsgrove	1,279	305	55	0	21	0	0	0	1,660
Bromsgrove	Alvechurch Village	2,054	Bromsgrove	972	385	76	0	77	0	0	0	1,510
Bromsgrove	Barnt Green and Hopwood	2,291	Bromsgrove	1,203	382	71	0	27	0	0	0	1,683
Bromsgrove	Cofton	1,918	Bromsgrove	944	353	55	0	57	0	0	0	1,409
Bromsgrove	Drakes Cross	2,445	Bromsgrove	1,233	466	70	0	27	0	0	0	1,796
Bromsgrove	Hollywood	2,397	Bromsgrove	1,253	418	67	0	24	0	0	0	1,762
Bromsgrove	Wythall East	2,237	Bromsgrove	1,147	404	68	0	24	0	0	0	1,643
Bromsgrove	Wythall West	2,089	Bromsgrove	1,019	354	141	0	21	0	0	0	1,535
Redditch	Abbey	4,278	Redditch	1,495	1,137	103	89	26	0	149	6	3,005
Redditch	Astwood Bank and Feckenham	4,270	Redditch	1,969	759	34	85	22	0	126	6	3,001
Redditch	Batchley and Brockhill	5,911	Redditch	2,004	1,747	55	131	32	0	177	8	4,154
Redditch	Central	4,651	Redditch	1,324	1,531	76	52	29	0	244	11	3,267
Redditch	Church Hill	5,836	Redditch	1,896	1,737	123	139	37	0	161	7	4,100
Redditch	Crabbs Cross	4,219	Redditch	1,842	780	86	93	25	0	132	6	2,964
Redditch	Greenlands	6,405	Redditch	1,960	1,968	151	150	44	0	218	10	4,501
Redditch	Headless Cross and Oakenshaw	6,374	Redditch	2,511	1,446	141	144	39	0	191	8	4,480
Redditch	Lodge Park	4,072	Redditch	1,179	1,351	78	90	26	0	131	6	2,861
Redditch	Matchborough	4,364	Redditch	1,614	1,077	107	99	30	0	134	6	3,067
Redditch	West	3,942	Redditch	1,775	721	48	84	24	0	113	5	2,770
Redditch	Winyates	6,045	Redditch	2,140	1,575	156	145	39	0	184	8	4,247
	Total	78,058		30,759	18,896	1,761	1,301	651	0	1,960	87	55,415

And these are the implied results for 2017 for the new seat of Redditch. 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:	Rachel Maclean (CON)
County/Area:	Hereford and Worcestershire (West Midlands)
Electorate:	78,058
Turnout:	71.0%

Redditch: New Boundaries 2018 Calculation

Redditch: Overview

Introduction