New Seat Details

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Torfaen 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
LAB	26,984	55.7%
CON	16,253	33.5%
Plaid	2,231	4.6%
UKIP	1,712	3.5%
LIB	1,143	2.4%
Green	136	0.3%
LAB Majority	10,731	22.1%

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.

Torfaen: Map

List of old seats forming part of Torfaen

Old seat: Monmouth

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

Old seat: Monmouth				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	Plaid Votes	MIN Votes	OTH Votes	Total Votes
Monmouthshire	Caerwent	1,615	Monmouthshire	692	313	20	14	14	23	0	0	1,076
Monmouthshire	Cantref	1,579	Monmouthshire	684	423	41	16	21	22	0	0	1,207
Monmouthshire	Castle	1,507	Monmouthshire	642	376	86	19	22	26	0	0	1,171
Monmouthshire	Croesonen	1,607	Monmouthshire	442	788	40	20	23	23	0	0	1,336
Monmouthshire	Crucorney	1,691	Monmouthshire	791	372	29	18	22	45	0	0	1,277
Monmouthshire	Devauden	1,174	Monmouthshire	611	179	55	10	13	19	0	0	887
Monmouthshire	Dixton with Osbaston	1,793	Monmouthshire	792	393	164	24	33	33	0	0	1,439
Monmouthshire	Drybridge	2,423	Monmouthshire	930	850	71	31	91	127	0	0	2,100
Monmouthshire	Goetre Fawr	1,833	Monmouthshire	987	355	34	19	21	24	0	0	1,440
Monmouthshire	Grofield	1,285	Monmouthshire	433	473	120	20	26	33	0	0	1,105
Monmouthshire	Lansdown	1,540	Monmouthshire	392	817	44	21	22	18	0	0	1,314
Monmouthshire	Larkfield	1,475	Monmouthshire	542	412	114	24	24	39	0	0	1,155
Monmouthshire	Llanbadoc	1,014	Monmouthshire	468	232	18	11	15	19	0	0	763
Monmouthshire	Llanelly Hill	3,014	Monmouthshire	1,211	767	74	40	46	182	0	0	2,320
Monmouthshire	Llanfoist Fawr	1,616	Monmouthshire	758	324	26	16	20	19	0	0	1,163
Monmouthshire	Llangybi Fawr	1,439	Monmouthshire	793	230	17	12	15	32	0	0	1,099
Monmouthshire	Llanover	1,717	Monmouthshire	887	386	16	13	17	16	0	0	1,335
Monmouthshire	Llantilio Crossenny	1,422	Monmouthshire	721	225	18	11	15	33	0	0	1,023
Monmouthshire	Llanwenarth Ultra	1,073	Monmouthshire	352	404	19	12	13	14	0	0	814
Monmouthshire	Mardy	1,331	Monmouthshire	548	312	69	18	20	41	0	0	1,008
Monmouthshire	Mitchel Troy	953	Monmouthshire	537	161	15	8	10	22	0	0	753
Monmouthshire	Overmonnow	1,509	Monmouthshire	648	615	52	19	27	35	0	0	1,396
Monmouthshire	Portskewett	1,684	Monmouthshire	675	481	29	19	18	36	0	0	1,258
Monmouthshire	Priory	1,437	Monmouthshire	526	494	97	21	22	30	0	0	1,190
Monmouthshire	Raglan	1,510	Monmouthshire	697	369	27	17	18	28	0	0	1,156
Monmouthshire	Shirenewton	1,754	Monmouthshire	815	369	61	18	25	27	0	0	1,315
Monmouthshire	St Arvans	1,253	Monmouthshire	695	203	18	10	14	15	0	0	955
Monmouthshire	St Christopher's	1,762	Monmouthshire	556	860	52	25	27	41	0	0	1,561
Monmouthshire	St Kingsmark	2,226	Monmouthshire	1,144	420	147	24	31	29	0	0	1,795
Monmouthshire	St Mary's	1,414	Monmouthshire	482	528	113	21	28	48	0	0	1,220
Monmouthshire	Thornwell	1,860	Monmouthshire	608	873	46	26	23	37	0	0	1,613
Monmouthshire	Trellech United	2,122	Monmouthshire	1,065	422	37	20	28	40	0	0	1,612
Monmouthshire	Usk	1,862	Monmouthshire	1,141	391	65	22	32	32	0	0	1,683
Monmouthshire	Wyesham	1,644	Monmouthshire	620	489	46	19	63	35	0	0	1,272
Torfaen	Croesyceiliog North	2,580	Torfaen	752	1,124	66	34	33	29	0	0	2,038
Torfaen	Croesyceiliog South	1,420	Torfaen	434	531	30	42	17	23	0	0	1,077
Torfaen	Llanyrafon North	1,492	Torfaen	423	668	47	22	20	17	0	0	1,197
Torfaen	Llanyrafon South	2,099	Torfaen	915	578	43	27	24	27	0	0	1,614
	Total	62,729		26,409	18,207	2,066	763	953	1,339	0	0	49,737

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

Old seat: Newport West

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

Old seat: Newport West				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	Plaid Votes	MIN Votes	OTH Votes	Total Votes
Newport	Allt-yr-Yn	6,368	Newport	2,238	1,846	98	111	49	149	0	0	4,491
Newport	Bettws (Newport)	5,275	Newport	1,089	2,572	42	107	38	30	0	0	3,878
Newport	Caerleon	6,214	Torfaen	1,836	1,952	104	97	42	74	0	0	4,105
Newport	Gaer	6,084	Newport	1,436	2,614	106	119	43	120	0	0	4,438
Newport	Graig (Newport)	4,723	Caerphilly	1,690	1,208	88	77	27	46	0	0	3,136
Newport	Malpas	5,939	Newport	1,503	2,239	74	104	104	58	0	0	4,082
Newport	Marshfield	4,554	Newport	1,802	1,066	93	87	27	106	0	0	3,181
Newport	Pillgwenlly	4,067	Newport	854	2,453	103	93	43	182	0	0	3,728
Newport	Rogerstone	7,743	Caerphilly	2,401	2,368	112	120	44	90	0	0	5,135
Newport	Shaftesbury	3,548	Newport	705	1,625	40	75	29	122	0	0	2,596
Newport	Stow Hill	2,794	Newport	844	1,339	59	58	33	88	0	0	2,421
Newport	Tredegar Park	2,792	Newport	667	1,443	58	52	18	13	0	0	2,251
	Total	60,101		17,065	22,725	977	1,100	497	1,078	0	0	43,442

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

Old seat: Torfaen

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

Old seat: Torfaen				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	Plaid Votes	MIN Votes	OTH Votes	Total Votes
Torfaen	Abersychan	5,142	Torfaen	957	2,102	44	124	0	148	0	0	3,375
Torfaen	Blaenavon	4,353	Torfaen	802	1,696	164	105	0	89	0	0	2,856
Torfaen	Brynwern	1,325	Torfaen	224	559	16	31	0	39	0	0	869
Torfaen	Coed Eva	1,689	Torfaen	376	541	22	45	0	124	0	0	1,108
Torfaen	Cwmyniscoy	1,029	Torfaen	175	449	8	23	0	20	0	0	675
Torfaen	Fairwater	3,773	Torfaen	797	1,284	52	102	0	241	0	0	2,476
Torfaen	Greenmeadow	2,989	Torfaen	512	1,263	47	66	0	74	0	0	1,962
Torfaen	Llantarnam	3,977	Torfaen	940	1,417	48	97	0	109	0	0	2,611
Torfaen	New Inn	4,312	Torfaen	1,481	1,123	40	91	0	94	0	0	2,829
Torfaen	Panteg	5,251	Torfaen	1,045	1,913	128	166	0	194	0	0	3,446
Torfaen	Pontnewydd	4,548	Torfaen	778	1,838	60	107	0	202	0	0	2,985
Torfaen	Pontnewynydd	1,070	Torfaen	226	410	11	28	0	27	0	0	702
Torfaen	Pontypool	1,280	Torfaen	282	444	16	34	0	63	0	0	839
Torfaen	Snatchwood	1,456	Torfaen	229	605	10	75	0	38	0	0	957
Torfaen	St Cadocs and Penygarn	1,128	Torfaen	213	438	11	28	0	50	0	0	740
Torfaen	St Dials	2,607	Torfaen	521	984	29	71	0	106	0	0	1,711
Torfaen	Trevethin	2,610	Torfaen	414	1,123	19	61	0	96	0	0	1,713
Torfaen	Two Locks	4,501	Torfaen	915	1,713	60	102	0	163	0	0	2,953
Torfaen	Upper Cwmbran	3,783	Torfaen	627	1,586	46	89	0	133	0	0	2,481
Torfaen	Wainfelin	1,736	Torfaen	379	643	22	45	0	51	0	0	1,140
	Total	58,559		11,893	22,131	853	1,490	0	2,061	0	0	38,428

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

New seat: Torfaen

District	Ward	Electorate 2017	Old Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	Plaid Votes	MIN Votes	OTH Votes	Total Votes
New seat: Torfaen
Newport	Caerleon	6,083	Newport West	1,836	1,952	104	97	42	74	0	0	4,105
Torfaen	Abersychan	5,430	Torfaen	957	2,102	44	124	0	148	0	0	3,375
Torfaen	Blaenavon	4,597	Torfaen	802	1,696	164	105	0	89	0	0	2,856
Torfaen	Brynwern	1,399	Torfaen	224	559	16	31	0	39	0	0	869
Torfaen	Coed Eva	1,784	Torfaen	376	541	22	45	0	124	0	0	1,108
Torfaen	Croesyceiliog North	2,660	Monmouth	752	1,124	66	34	33	29	0	0	2,038
Torfaen	Croesyceiliog South	1,404	Monmouth	434	531	30	42	17	23	0	0	1,077
Torfaen	Cwmyniscoy	1,087	Torfaen	175	449	8	23	0	20	0	0	675
Torfaen	Fairwater	3,984	Torfaen	797	1,284	52	102	0	241	0	0	2,476
Torfaen	Greenmeadow	3,156	Torfaen	512	1,263	47	66	0	74	0	0	1,962
Torfaen	Llantarnam	4,200	Torfaen	940	1,417	48	97	0	109	0	0	2,611
Torfaen	Llanyrafon North	1,563	Monmouth	423	668	47	22	20	17	0	0	1,197
Torfaen	Llanyrafon South	2,104	Monmouth	915	578	43	27	24	27	0	0	1,614
Torfaen	New Inn	4,553	Torfaen	1,481	1,123	40	91	0	94	0	0	2,829
Torfaen	Panteg	5,545	Torfaen	1,045	1,913	128	166	0	194	0	0	3,446
Torfaen	Pontnewydd	4,803	Torfaen	778	1,838	60	107	0	202	0	0	2,985
Torfaen	Pontnewynydd	1,130	Torfaen	226	410	11	28	0	27	0	0	702
Torfaen	Pontypool	1,352	Torfaen	282	444	16	34	0	63	0	0	839
Torfaen	Snatchwood	1,538	Torfaen	229	605	10	75	0	38	0	0	957
Torfaen	St Cadocs and Penygarn	1,191	Torfaen	213	438	11	28	0	50	0	0	740
Torfaen	St Dials	2,753	Torfaen	521	984	29	71	0	106	0	0	1,711
Torfaen	Trevethin	2,756	Torfaen	414	1,123	19	61	0	96	0	0	1,713
Torfaen	Two Locks	4,753	Torfaen	915	1,713	60	102	0	163	0	0	2,953
Torfaen	Upper Cwmbran	3,995	Torfaen	627	1,586	46	89	0	133	0	0	2,481
Torfaen	Wainfelin	1,833	Torfaen	379	643	22	45	0	51	0	0	1,140
	Total	75,653		16,253	26,984	1,143	1,712	136	2,231	0	0	48,459

And these are the implied results for 2017 for the new seat of Torfaen. 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:	Nick Thomas-Symonds (LAB)
County/Area:	Gwent (Wales)
Electorate:	75,653
Turnout:	64.1%

Torfaen: New Boundaries 2018 Calculation

Torfaen: Overview

Introduction