New Boundaries 2013 Calculation

This page shows the detail of the calculations performed to estimate the general election result for 2010 had the new boundaries for Brentwood and Ongar 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 2010. 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.

Due to changes in ward boundaries, some new wards are divided among several old constituencies (and sometimes in Scotland between two new constituencies). Such wards are shown divided into several parts, called [1], [2], and so on.

Election results from a recent local election are given. This is usually the local election closest to 2010 from the period 2007-2011. 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. Where zero votes are shown, the ward results have not yet been acquired, and the implied result is still provisional and will be improved later.

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% of its votes from each ward. 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 on a ward-by-ward basis using these common percentages.

List of old seats forming part of Brentwood and Ongar

Old seat: Brentwood and Ongar

The raw vote table shows the district council election results for all the wards in the old seat of Brentwood and Ongar. The first block shows the actual results, the second block shows the turnout-adjusted results. Details of the transfer calculation are given below this table.

Old seat: Brentwood and Ongar				Actual Results				Turnout-adjusted Results
District	Ward	Election Year	Electorate 2010	CON Votes	LAB Votes	LIB Votes	OTH Votes	CON Votes	LAB Votes	LIB Votes	OTH Votes	Total Votes
Brentwood	Brentwood North	2010	4,556	1,327	271	1,527	0	1,378	281	1,585	0	3,244
Brentwood	Brentwood South	2010	4,211	1,221	544	846	262	1,274	568	883	273	2,998
Brentwood	Brentwood West	2010	4,973	1,578	273	1,579	0	1,629	282	1,630	0	3,541
Brentwood	Brizes and Doddinghurst	2010	4,704	1,790	209	974	362	1,798	210	978	364	3,350
Brentwood	Herongate, Ingrave and West Horndon	2010	2,940	1,403	175	609	0	1,343	168	583	0	2,094
Brentwood	Hutton Central	2010	2,885	1,409	175	507	0	1,384	172	498	0	2,054
Brentwood	Hutton East	2010	2,851	1,057	221	694	0	1,088	228	715	0	2,031
Brentwood	Hutton North	2011	3,079	636	150	141	594	917	216	203	856	2,192
Brentwood	Hutton South	2010	3,047	1,495	184	445	164	1,418	175	422	156	2,171
Brentwood	Ingatestone, Fryerning and Mountnessing	2010	4,769	1,894	308	971	372	1,815	295	930	356	3,396
Brentwood	Pilgrims Hatch	2010	4,553	1,760	403	2,900	330	1,058	242	1,744	198	3,242
Brentwood	Shenfield	2010	4,167	1,937	216	1,175	0	1,727	193	1,048	0	2,968
Brentwood	South Weald	2010	1,407	602	58	378	0	581	56	365	0	1,002
Brentwood	Tipps Cross	2011	3,042	1,018	176	261	0	1,516	262	389	0	2,167
Brentwood	Warley	2010	4,508	1,512	291	1,267	144	1,510	291	1,266	144	3,211
Epping Forest	Chipping Ongar, Greensted and Marden Ash	2010	3,313	1,855	0	1,824	702	999	0	982	378	2,359
Epping Forest	High Ongar, Willingale and The Rodings	2008	1,737	469	0	53	91	946	0	107	184	1,237
Epping Forest	Lambourne	2011	1,573	517	0	51	78	897	0	88	135	1,120
Epping Forest	Moreton and Fyfield	2008	1,720	329	0	315	82	555	0	531	138	1,224
Epping Forest	North Weald Bassett	2010	3,529	1,682	0	511	159	1,797	0	546	170	2,513
Epping Forest	Passingford	2008	1,772	537	0	66	0	1,124	0	138	0	1,262
Epping Forest	Shelley	2011	1,705	236	242	0	59	534	547	0	133	1,214
	Total		71,041					27,288	4,186	15,631	3,485	50,590

The transfer table below shows the votes cast in the old seat of Brentwood and Ongar at the general election, as well as the total local turnout-adjusted votes. The number of votes to transfer, shown in the fourth and fifth columns, are the difference between the general and local votes. Strong parties will have votes transferred away, and weak parties will have votes transferred into them. The final column describes how votes will be transferred away from or into that party on a ward-by-ward basis. If a party is too strong, it will lose a percentage of its votes in each ward which go into that ward's transfer pool. If a party is too weak, it will gain votes from each ward's transfer pool in proportion to the number of transfer votes it needs over the whole old seat.

Party	General Election 2010 Votes	Local Election Turnout-adjusted Votes	Votes to transfer away	Votes to transfer into	Ward Transfers needed
CON	28,793	27,288	0	1,505	Transfer in 40.0% (= 1505 / 3761) of ward's transfer pool votes
LAB	4,992	4,186	0	806	Transfer in 21.4% (= 806 / 3761) of ward's transfer pool votes
LIB	11,872	15,631	3,759	0	Transfer away 24.0% (= 3759 / 15631) of ward's LIB votes
OTH	4,935	3,485	0	1,450	Transfer in 38.6% (= 1450 / 3761) of ward's transfer pool votes
Total	50,592	50,590	3,761	3,761

Main table for Brentwood and Ongar

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

After transfer adjustment, the totals for each party over all the wards match the general election vote in the old seat.

Old seat: Basildon South and East Thurrock

Old seat: Brentwood and Ongar	Transfer-adjusted Results
District	Ward	Electorate 2010	New Seat	CON Votes	LAB Votes	LIB Votes	OTH Votes	Total Votes
Brentwood	Brentwood North	4,556	Brentwood and Ongar	1,531	363	1,204	147	3,244
Brentwood	Brentwood South	4,211	Brentwood and Ongar	1,359	614	671	355	2,998
Brentwood	Brentwood West	4,973	Brentwood and Ongar	1,786	366	1,238	151	3,541
Brentwood	Brizes and Doddinghurst	4,704	Brentwood and Ongar	1,892	260	743	455	3,350
Brentwood	Herongate, Ingrave and West Horndon	2,940	Brentwood and Ongar	1,399	198	443	54	2,094
Brentwood	Hutton Central	2,885	Brentwood and Ongar	1,432	198	378	46	2,054
Brentwood	Hutton East	2,851	Brentwood and Ongar	1,157	265	543	66	2,031
Brentwood	Hutton North	3,079	Brentwood and Ongar	937	226	154	875	2,192
Brentwood	Hutton South	3,047	Brentwood and Ongar	1,459	197	321	195	2,171
Brentwood	Ingatestone, Fryerning and Mountnessing	4,769	Brentwood and Ongar	1,904	343	706	442	3,396
Brentwood	Pilgrims Hatch	4,553	Brentwood and Ongar	1,226	332	1,325	360	3,242
Brentwood	Shenfield	4,167	Brentwood and Ongar	1,828	247	796	97	2,968
Brentwood	South Weald	1,407	Brentwood and Ongar	616	75	277	34	1,002
Brentwood	Tipps Cross	3,042	Brentwood and Ongar	1,553	282	295	36	2,167
Brentwood	Warley	4,508	Brentwood and Ongar	1,632	356	962	261	3,211
Epping Forest	Chipping Ongar, Greensted and Marden Ash	3,313	Brentwood and Ongar	1,093	51	746	469	2,359
Epping Forest	High Ongar, Willingale and The Rodings	1,737	Brentwood and Ongar	956	6	81	194	1,237
Epping Forest	Lambourne	1,573	Epping Forest	905	5	67	143	1,120
Epping Forest	Moreton and Fyfield	1,720	Brentwood and Ongar	606	27	403	187	1,224
Epping Forest	North Weald Bassett	3,529	Brentwood and Ongar	1,850	28	415	221	2,513
Epping Forest	Passingford	1,772	Brentwood and Ongar	1,137	7	105	13	1,262
Epping Forest	Shelley	1,705	Brentwood and Ongar	534	547	0	133	1,214
	Total	71,041		28,792	4,993	11,873	4,934	50,590

The raw vote table shows the district council election results for all the wards in the old seat of Basildon South and East Thurrock. The first block shows the actual results, the second block shows the turnout-adjusted results. Details of the transfer calculation are given below this table.

Old seat: Basildon South and East Thurrock				Actual Results				Turnout-adjusted Results
District	Ward	Election Year	Electorate 2010	CON Votes	LAB Votes	LIB Votes	OTH Votes	CON Votes	LAB Votes	LIB Votes	OTH Votes	Total Votes
Basildon	Langdon Hills	2010	6,900	2,594	875	769	555	2,326	785	690	498	4,299
Basildon	Nethermayne	2010	8,748	1,727	1,312	2,017	487	1,698	1,290	1,983	479	5,450
Basildon	Pitsea North West	2010	9,136	1,654	1,508	770	913	1,943	1,771	904	1,072	5,690
Basildon	Pitsea South East	2010	8,457	1,973	1,577	576	839	2,093	1,673	611	890	5,267
Basildon	Vange	2011	6,750	554	1,089	102	338	1,118	2,198	206	682	4,204
Thurrock	Corringham and Fobbing	2011	4,485	909	666	88	290	1,300	953	126	415	2,794
Thurrock	East Tilbury	2011	4,746	211	303	56	1,012	394	566	105	1,891	2,956
Thurrock	Orsett	2010	4,772	1,922	729	0	632	1,740	660	0	572	2,972
Thurrock	Stanford East and Corringham Town	2010	6,476	1,649	1,620	0	868	1,608	1,580	0	846	4,034
Thurrock	Stanford-le-Hope West	2011	4,682	720	653	73	374	1,154	1,046	117	599	2,916
Thurrock	The Homesteads	2010	6,667	2,045	1,662	0	957	1,821	1,480	0	852	4,153
	Total		71,819					17,195	14,002	4,742	8,796	44,735

The transfer table below shows the votes cast in the old seat of Basildon South and East Thurrock at the general election, as well as the total local turnout-adjusted votes. The number of votes to transfer, shown in the fourth and fifth columns, are the difference between the general and local votes. Strong parties will have votes transferred away, and weak parties will have votes transferred into them. The final column describes how votes will be transferred away from or into that party on a ward-by-ward basis. If a party is too strong, it will lose a percentage of its votes in each ward which go into that ward's transfer pool. If a party is too weak, it will gain votes from each ward's transfer pool in proportion to the number of transfer votes it needs over the whole old seat.

Party	General Election 2010 Votes	Local Election Turnout-adjusted Votes	Votes to transfer away	Votes to transfer into	Ward Transfers needed
CON	19,624	17,195	0	2,429	Transfer in 66.3% (= 2429 / 3664) of ward's transfer pool votes
LAB	13,852	14,002	150	0	Transfer away 1.1% (= 150 / 14002) of ward's LAB votes
LIB	5,977	4,742	0	1,235	Transfer in 33.7% (= 1235 / 3664) of ward's transfer pool votes
OTH	5,282	8,796	3,514	0	Transfer away 39.9% (= 3514 / 8796) of ward's OTH votes
Total	44,735	44,735	3,664	3,664

Main table for Basildon South and East Thurrock

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