New Seat Details - Chatham and Malling

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Chatham and Malling 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	29,669	57.6%
LAB	16,158	31.4%
UKIP	2,525	4.9%
LIB	2,061	4.0%
Green	827	1.6%
OTH	233	0.5%
CON Majority	13,511	26.2%

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.

Chatham and Malling: Map

List of old seats forming part of Chatham and Malling

Old seat: Chatham and Aylesford

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

Old seat: Chatham and Aylesford				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
Medway	Chatham Central	8,996	Chatham and Malling	3,096	3,733	123	444	140	0	0	51	7,587
Medway	Lordswood and Capstone	6,393	Gillingham and Rainham	2,692	1,224	67	126	32	0	0	25	4,166
Medway	Luton and Wayfield	8,936	Chatham and Malling	3,048	2,896	90	463	68	0	0	69	6,634
Medway	Princes Park	6,837	Chatham and Malling	2,836	1,538	72	329	37	0	0	21	4,833
Medway	Walderslade	6,956	Chatham and Malling	2,678	1,285	136	279	36	0	0	28	4,442
Tonbridge and Malling	Aylesford North and Walderslade	4,948	Chatham and Malling	2,127	649	45	82	24	0	0	8	2,935
Tonbridge and Malling	Aylesford South	3,180	Chatham and Malling	1,419	394	72	54	14	0	0	7	1,960
Tonbridge and Malling	Burham and Wouldham	2,065	Chatham and Malling	840	297	21	38	39	0	0	10	1,245
Tonbridge and Malling	Ditton	3,707	Chatham and Malling	1,510	517	33	63	54	0	0	8	2,185
Tonbridge and Malling	Larkfield North	3,402	Chatham and Malling	1,487	509	127	66	18	0	0	8	2,215
Tonbridge and Malling	Larkfield South	3,228	Chatham and Malling	1,200	512	123	64	70	0	0	11	1,980
Tonbridge and Malling	Snodland East and Ham Hill	3,476	Chatham and Malling	1,241	810	104	145	23	0	0	6	2,329
Tonbridge and Malling	Snodland West and Holborough Lakes	4,257	Chatham and Malling	1,411	767	104	72	19	0	0	6	2,379
	Total	66,381		25,585	15,131	1,117	2,225	574	0	0	258	44,890

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

Old seat: Tonbridge and Malling

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

Old seat: Tonbridge and Malling				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
Sevenoaks	Cowden and Hever	1,561	Tonbridge	909	176	35	41	26	0	0	0	1,187
Sevenoaks	Edenbridge North and East	3,616	Tonbridge	1,727	620	122	56	128	0	0	0	2,653
Sevenoaks	Edenbridge South and West	3,015	Tonbridge	1,474	693	102	97	100	0	0	0	2,466
Sevenoaks	Leigh and Chiddingstone Causeway	1,690	Tonbridge	1,021	175	41	19	27	0	0	0	1,283
Sevenoaks	Penshurst, Fordcombe and Chiddingstone	1,966	Tonbridge	938	235	154	22	69	0	0	0	1,418
Tonbridge and Malling	Borough Green and Long Mill	5,258	Tonbridge	2,664	811	177	171	146	0	0	0	3,969
Tonbridge and Malling	Cage Green	3,502	Tonbridge	1,728	603	122	54	127	0	0	0	2,634
Tonbridge and Malling	Castle	3,287	Tonbridge	1,759	540	356	57	148	0	0	0	2,860
Tonbridge and Malling	Downs and Mereworth	3,305	Tonbridge	1,743	414	72	85	108	0	0	0	2,422
Tonbridge and Malling	East Malling	3,527	Chatham and Malling	1,558	767	382	127	87	0	0	0	2,921
Tonbridge and Malling	Hadlow and East Peckham	5,371	Tonbridge	2,818	830	163	153	193	0	0	0	4,157
Tonbridge and Malling	Higham	3,611	Tonbridge	1,838	591	128	54	130	0	0	0	2,741
Tonbridge and Malling	Hildenborough	3,686	Tonbridge	1,815	533	249	103	133	0	0	0	2,833
Tonbridge and Malling	Judd	3,594	Tonbridge	1,584	849	264	120	156	0	0	0	2,973
Tonbridge and Malling	Kings Hill	5,645	Chatham and Malling	3,191	816	193	167	97	0	0	0	4,464
Tonbridge and Malling	Medway	4,167	Tonbridge	1,734	958	172	123	139	0	0	0	3,126
Tonbridge and Malling	Trench	3,516	Tonbridge	1,457	931	171	110	101	0	0	0	2,770
Tonbridge and Malling	Vauxhall	3,693	Tonbridge	1,491	858	333	54	153	0	0	0	2,889
Tonbridge and Malling	Wateringbury	1,540	Tonbridge	875	209	41	22	55	0	0	0	1,202
Tonbridge and Malling	West Malling and Leybourne	4,794	Chatham and Malling	2,027	668	436	132	101	0	0	0	3,364
Tonbridge and Malling	Wrotham, Ightham and Stansted	3,273	Sevenoaks	1,869	432	75	87	110	0	0	0	2,573
	Total	73,617		36,220	12,709	3,788	1,854	2,334	0	0	0	56,905

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

New seat: Chatham and Malling

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: Chatham and Malling
Medway	Chatham Central	11,901	Chatham and Aylesford	3,096	3,733	123	444	140	0	0	51	7,587
Medway	Luton and Wayfield	10,407	Chatham and Aylesford	3,048	2,896	90	463	68	0	0	69	6,634
Medway	Princes Park	7,580	Chatham and Aylesford	2,836	1,538	72	329	37	0	0	21	4,833
Medway	Walderslade	6,968	Chatham and Aylesford	2,678	1,285	136	279	36	0	0	28	4,442
Tonbridge and Malling	Aylesford North and Walderslade	4,606	Chatham and Aylesford	2,127	649	45	82	24	0	0	8	2,935
Tonbridge and Malling	Aylesford South	3,074	Chatham and Aylesford	1,419	394	72	54	14	0	0	7	1,960
Tonbridge and Malling	Burham and Wouldham	1,950	Chatham and Aylesford	840	297	21	38	39	0	0	10	1,245
Tonbridge and Malling	Ditton	3,427	Chatham and Aylesford	1,510	517	33	63	54	0	0	8	2,185
Tonbridge and Malling	East Malling	3,964	Tonbridge and Malling	1,558	767	382	127	87	0	0	0	2,921
Tonbridge and Malling	Kings Hill	6,058	Tonbridge and Malling	3,191	816	193	167	97	0	0	0	4,464
Tonbridge and Malling	Larkfield North	3,476	Chatham and Aylesford	1,487	509	127	66	18	0	0	8	2,215
Tonbridge and Malling	Larkfield South	3,106	Chatham and Aylesford	1,200	512	123	64	70	0	0	11	1,980
Tonbridge and Malling	Snodland East and Ham Hill	3,655	Chatham and Aylesford	1,241	810	104	145	23	0	0	6	2,329
Tonbridge and Malling	Snodland West and Holborough Lakes	3,732	Chatham and Aylesford	1,411	767	104	72	19	0	0	6	2,379
Tonbridge and Malling	West Malling and Leybourne	4,564	Tonbridge and Malling	2,027	668	436	132	101	0	0	0	3,364
	Total	78,468		29,669	16,158	2,061	2,525	827	0	0	233	51,473

And these are the implied results for 2017 for the new seat of Chatham and Malling. 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:	Tracey Crouch (CON)
County/Area:	Kent (South East)
Electorate:	78,468
Turnout:	65.6%

Chatham and Malling: New Boundaries 2018 Calculation

Chatham and Malling: Overview

Introduction