New Seat Details - Plympton, Tavistock and Ivybridge

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Plympton, Tavistock and Ivybridge 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	33,475	59.5%
LAB	14,610	26.0%
LIB	5,508	9.8%
Green	1,429	2.5%
UKIP	1,000	1.8%
OTH	246	0.4%
CON Majority	18,865	33.5%

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.

Plympton, Tavistock and Ivybridge: Map

List of old seats forming part of Plympton, Tavistock and Ivybridge

Old seat: Devon South West

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

Old seat: Devon South West				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
Plymouth	Plympton Chaddlewood	5,945	Plympton, Tavistock and Ivybridge	2,648	1,795	180	196	58	0	0	0	4,877
Plymouth	Plympton Erle	6,680	Plympton, Tavistock and Ivybridge	2,829	1,817	311	185	125	0	0	0	5,267
Plymouth	Plympton St Mary	9,973	Plympton, Tavistock and Ivybridge	4,602	2,313	290	266	182	0	0	0	7,653
Plymouth	Plymstock Dunstone	9,465	Plymouth Sutton and Devonport	4,256	2,242	398	264	149	0	0	0	7,309
Plymouth	Plymstock Radford	9,800	Plymouth Sutton and Devonport	4,251	2,534	287	268	97	0	0	0	7,437
South Hams	Bickleigh and Cornwood	2,197	Plympton, Tavistock and Ivybridge	1,097	371	108	24	40	0	0	0	1,640
South Hams	Charterlands	2,217	Plympton, Tavistock and Ivybridge	1,143	377	43	23	45	0	0	0	1,631
South Hams	Ermington and Ugborough	2,195	Plympton, Tavistock and Ivybridge	1,010	359	122	20	38	0	0	0	1,549
South Hams	Ivybridge East	4,201	Plympton, Tavistock and Ivybridge	1,883	1,018	311	110	87	0	0	0	3,409
South Hams	Ivybridge West	4,634	Plympton, Tavistock and Ivybridge	2,444	948	131	60	96	0	0	0	3,679
South Hams	Loddiswell and Aveton Gifford	763	Totnes	375	122	14	7	15	0	0	0	533
South Hams	Newton and Yealmpton	4,785	Plympton, Tavistock and Ivybridge	2,180	802	286	45	94	0	0	0	3,407
South Hams	Wembury and Brixton	3,664	Plympton, Tavistock and Ivybridge	1,761	600	184	39	62	0	0	0	2,646
South Hams	Woolwell	2,215	Plympton, Tavistock and Ivybridge	1,156	519	65	32	47	0	0	0	1,819
	Total	68,734		31,635	15,817	2,730	1,539	1,135	0	0	0	52,856

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

Old seat: Devon West and Torridge

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

Old seat: Devon West and Torridge				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
Torridge	Appledore	2,216	Bideford, Bude and Launceston	978	354	305	0	60	0	0	26	1,723
Torridge	Bideford East	4,785	Bideford, Bude and Launceston	1,712	1,114	664	0	122	0	0	58	3,670
Torridge	Bideford North	4,277	Bideford, Bude and Launceston	1,500	1,087	805	0	117	0	0	52	3,561
Torridge	Bideford South	4,220	Bideford, Bude and Launceston	1,313	1,248	621	0	56	0	0	28	3,266
Torridge	Broadheath	1,371	Bideford, Bude and Launceston	759	144	120	0	13	0	0	8	1,044
Torridge	Clinton	1,251	Devon Central	540	179	170	0	32	0	0	19	940
Torridge	Clovelly Bay	1,224	Bideford, Bude and Launceston	606	195	163	0	17	0	0	7	988
Torridge	Coham Bridge	1,310	Bideford, Bude and Launceston	661	143	121	0	12	0	0	16	953
Torridge	Forest	1,420	Bideford, Bude and Launceston	709	163	149	0	28	0	0	13	1,062
Torridge	Hartland and Bradworthy	2,438	Bideford, Bude and Launceston	1,029	370	347	0	68	0	0	29	1,843
Torridge	Holsworthy	3,269	Bideford, Bude and Launceston	1,416	458	439	0	63	0	0	15	2,391
Torridge	Kenwith	1,346	Bideford, Bude and Launceston	777	129	127	0	13	0	0	6	1,052
Torridge	Monkleigh and Littleham	1,232	Bideford, Bude and Launceston	510	160	148	0	29	0	0	14	861
Torridge	Northam	4,361	Bideford, Bude and Launceston	1,975	805	519	0	56	0	0	54	3,409
Torridge	Orchard Hill	1,453	Bideford, Bude and Launceston	632	150	140	0	16	0	0	6	944
Torridge	Shebbear and Langtree	1,538	Bideford, Bude and Launceston	850	180	159	0	30	0	0	7	1,226
Torridge	Tamarside	1,383	Bideford, Bude and Launceston	635	204	177	0	15	0	0	17	1,048
Torridge	Three Moors	1,339	Devon Central	682	147	141	0	27	0	0	6	1,003
Torridge	Torrington	4,240	Devon Central	1,713	906	682	0	133	0	0	59	3,493
Torridge	Two Rivers	1,498	Devon Central	755	137	129	0	14	0	0	10	1,045
Torridge	Waldon	1,378	Bideford, Bude and Launceston	632	200	171	0	13	0	0	17	1,033
Torridge	Westward Ho!	1,813	Bideford, Bude and Launceston	748	249	216	0	42	0	0	26	1,281
Torridge	Winkleigh	1,699	Devon Central	744	218	248	0	36	0	0	26	1,272
West Devon	Bere Ferrers	2,847	Plympton, Tavistock and Ivybridge	1,172	487	373	0	70	0	0	37	2,139
West Devon	Bridestowe	2,249	Devon Central	1,015	295	288	0	56	0	0	28	1,682
West Devon	Buckland Monachorum	2,969	Plympton, Tavistock and Ivybridge	1,407	380	396	0	74	0	0	31	2,288
West Devon	Burrator	2,866	Plympton, Tavistock and Ivybridge	1,235	448	415	0	80	0	0	34	2,212
West Devon	Dartmoor	1,363	Plympton, Tavistock and Ivybridge	897	210	198	0	38	0	0	8	1,351
West Devon	Mary Tavy	1,305	Plympton, Tavistock and Ivybridge	585	168	164	0	15	0	0	16	948
West Devon	Milton Ford	1,454	Plympton, Tavistock and Ivybridge	801	171	158	0	15	0	0	14	1,159
West Devon	Tamarside	1,400	Plympton, Tavistock and Ivybridge	670	193	167	0	15	0	0	16	1,061
West Devon	Tavistock North	3,696	Plympton, Tavistock and Ivybridge	1,627	666	586	0	114	0	0	47	3,040
West Devon	Tavistock South East	2,946	Plympton, Tavistock and Ivybridge	1,361	398	366	0	67	0	0	28	2,220
West Devon	Tavistock South West	2,823	Plympton, Tavistock and Ivybridge	967	570	654	0	67	0	0	15	2,273
	Total	76,979		33,613	12,926	10,526	0	1,623	0	0	793	59,481

The full details of these calculations are given on the Devon West and Torridge seat details page. Click on "Show workings".

New seat: Plympton, Tavistock and Ivybridge

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: Plympton, Tavistock and Ivybridge
Plymouth	Plympton Chaddlewood	6,576	Devon South West	2,648	1,795	180	196	58	0	0	0	4,877
Plymouth	Plympton Erle	7,100	Devon South West	2,829	1,817	311	185	125	0	0	0	5,267
Plymouth	Plympton St Mary	10,319	Devon South West	4,602	2,313	290	266	182	0	0	0	7,653
South Hams	Bickleigh and Cornwood	2,210	Devon South West	1,097	371	108	24	40	0	0	0	1,640
South Hams	Charterlands	2,199	Devon South West	1,143	377	43	23	45	0	0	0	1,631
South Hams	Ermington and Ugborough	2,089	Devon South West	1,010	359	122	20	38	0	0	0	1,549
South Hams	Ivybridge East	4,597	Devon South West	1,883	1,018	311	110	87	0	0	0	3,409
South Hams	Ivybridge West	4,960	Devon South West	2,444	948	131	60	96	0	0	0	3,679
South Hams	Newton and Yealmpton	4,592	Devon South West	2,180	802	286	45	94	0	0	0	3,407
South Hams	Wembury and Brixton	3,568	Devon South West	1,761	600	184	39	62	0	0	0	2,646
South Hams	Woolwell	2,453	Devon South West	1,156	519	65	32	47	0	0	0	1,819
West Devon	Bere Ferrers	2,897	Devon West and Torridge	1,172	487	373	0	70	0	0	37	2,139
West Devon	Buckland Monachorum	3,099	Devon West and Torridge	1,407	380	396	0	74	0	0	31	2,288
West Devon	Burrator	2,995	Devon West and Torridge	1,235	448	415	0	80	0	0	34	2,212
West Devon	Dartmoor	1,829	Devon West and Torridge	897	210	198	0	38	0	0	8	1,351
West Devon	Mary Tavy	1,284	Devon West and Torridge	585	168	164	0	15	0	0	16	948
West Devon	Milton Ford	1,570	Devon West and Torridge	801	171	158	0	15	0	0	14	1,159
West Devon	Tamarside	1,436	Devon West and Torridge	670	193	167	0	15	0	0	16	1,061
West Devon	Tavistock North	4,115	Devon West and Torridge	1,627	666	586	0	114	0	0	47	3,040
West Devon	Tavistock South East	3,004	Devon West and Torridge	1,361	398	366	0	67	0	0	28	2,220
West Devon	Tavistock South West	3,077	Devon West and Torridge	967	570	654	0	67	0	0	15	2,273
	Total	75,969		33,475	14,610	5,508	1,000	1,429	0	0	246	56,268

And these are the implied results for 2017 for the new seat of Plympton, Tavistock and Ivybridge. 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:	Gary Streeter (CON)
County/Area:	Devon (South West)
Electorate:	75,969
Turnout:	74.1%

Plympton, Tavistock and Ivybridge: New Boundaries 2018 Calculation

Plympton, Tavistock and Ivybridge: Overview

Introduction