Clwyd South: New Boundaries Calculation

Due to changes in ward boundaries, some new wards are divided among several old constituencies (though never 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 from 2003, 2004 or 2006. 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 is not needed because the entire old seat is unsplit.

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.

More details of the calculation formulas are available.

The old seat(s) needed are:

• Clwyd South

Old seat: Clwyd South

					Actual Results					Turnout-adjusted Results						Transfer-adjusted Results
District	Ward	Electorate 2005	Old Seat	New Seat	CON Votes	LAB Votes	LIB Votes	NAT Votes	OTH Votes	CON Votes	LAB Votes	LIB Votes	NAT Votes	OTH Votes	Total Votes	CON Votes	LAB Votes	LIB Votes	NAT Votes	OTH Votes	Total Votes
Denbighshire	Corwen	1,699	Clwyd South	Clwyd South	142	0	0	276	499	161	0	0	313	565	1,039	326	207	106	350	47	1,039
Denbighshire	Efenechtyd [1]	257	Clwyd South	Clwyd West	0	0	0	-1	0	0	0	0	157	0	157	0	0	0	157	0	157
Denbighshire	Llanarmon-yn-Ial/Llandegla [1]	384	Clwyd South	Clwyd West	429	0	501	0	0	108	0	126	0	0	234	108	0	126	0	0	234
Denbighshire	Llandrillo	864	Clwyd South	Clwyd South	0	0	0	391	158	0	0	0	376	152	528	44	55	28	386	12	528
Denbighshire	Llanfair Dyffryn Clwyd/Gwyddelwern [1]	660	Clwyd South	Clwyd West	0	0	147	273	592	0	0	59	109	236	404	69	86	103	124	19	404
Denbighshire	Llangollen	2,956	Clwyd South	Clwyd South	281	154	266	659	1,228	196	108	186	460	858	1,808	447	423	347	517	72	1,808
Powys	Llanrhaeadr-ym-Mochnant/Llansilin	1,358	Clwyd South	Montgomeryshire	0	0	0	0	835	0	0	0	0	830	830	243	304	156	55	69	830
Wrexham	Bronington	2,469	Clwyd South	Clwyd South	-1	0	0	0	0	1,510	0	0	0	0	1,510	1,510	0	0	0	0	1,510
Wrexham	Brymbo	2,019	Clwyd South	Clwyd South	0	165	0	0	702	0	235	0	0	1,000	1,235	293	602	188	66	83	1,235
Wrexham	Bryn Cefn	1,477	Clwyd South	Clwyd South	0	281	0	0	267	0	463	0	0	440	903	129	624	82	29	36	903
Wrexham	Cefn	3,614	Clwyd South	Clwyd South	0	1,321	166	0	1,086	0	1,134	143	0	933	2,210	273	1,476	318	62	78	2,210
Wrexham	Chirk North	1,867	Clwyd South	Clwyd South	0	161	0	0	532	0	265	0	0	876	1,141	256	586	165	58	73	1,141
Wrexham	Chirk South	1,405	Clwyd South	Clwyd South	0	333	0	0	354	0	416	0	0	443	859	129	578	83	29	37	859
Wrexham	Coedpoeth	3,575	Clwyd South	Clwyd South	0	541	291	0	1,415	0	526	283	0	1,376	2,185	403	1,031	542	92	115	2,185
Wrexham	Dyffryn Ceiriog/Ceiriog Valley	1,740	Clwyd South	Clwyd South	0	0	0	259	616	0	0	0	315	749	1,064	219	275	141	365	62	1,064
Wrexham	Esclusham	2,000	Clwyd South	Clwyd South	0	265	0	0	704	0	334	0	0	888	1,222	260	660	167	59	74	1,222
Wrexham	Gwenfro	1,239	Clwyd South	Clwyd South	0	-1	0	0	0	0	758	0	0	0	758	0	758	0	0	0	758
Wrexham	Johnstown	2,521	Clwyd South	Clwyd South	0	444	0	0	492	0	731	0	0	810	1,541	237	1,028	152	54	68	1,541
Wrexham	Llangollen Rural	1,527	Clwyd South	Clwyd South	0	146	0	0	598	0	183	0	0	750	933	219	458	141	50	62	933
Wrexham	Marchwiel	1,870	Clwyd South	Clwyd South	0	84	0	0	768	0	113	0	0	1,031	1,144	302	491	194	69	86	1,144
Wrexham	Minera	1,923	Clwyd South	Clwyd South	0	364	0	0	358	0	593	0	0	583	1,176	170	807	109	39	48	1,176
Wrexham	New Broughton	2,474	Clwyd South	Clwyd South	0	348	0	0	439	0	669	0	0	844	1,513	247	979	159	56	70	1,513
Wrexham	Overton	2,344	Clwyd South	Clwyd South	-1	0	0	0	0	1,433	0	0	0	0	1,433	1,433	0	0	0	0	1,433
Wrexham	Pant	1,642	Clwyd South	Clwyd South	0	221	0	0	486	0	314	0	0	690	1,004	202	567	130	46	57	1,004
Wrexham	Penycae	1,580	Clwyd South	Clwyd South	0	221	0	0	302	0	408	0	0	558	966	163	612	105	37	46	966
Wrexham	Penycae and Ruabon South	1,812	Clwyd South	Clwyd South	0	192	0	0	562	0	282	0	0	826	1,108	242	585	155	55	69	1,108
Wrexham	Plas Madoc	1,180	Clwyd South	Clwyd South	0	133	100	0	131	0	264	198	0	260	722	76	359	246	17	21	722
Wrexham	Ponciau	3,531	Clwyd South	Clwyd South	0	423	910	0	1,319	0	344	741	0	1,074	2,159	314	738	943	71	90	2,159
Wrexham	Ruabon	1,873	Clwyd South	Clwyd South	0	209	76	140	282	0	339	123	227	457	1,146	134	506	209	257	38	1,146
	Total		Clwyd South							3,408	8,479	1,859	1,957	17,229	32,932	8,460	14,808	5,105	3,111	1,446	32,932

The transfer table below shows the votes cast in the old seat of Clwyd South 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 2005 Votes	Local Election Turnout-adjusted Votes	Votes to transfer away	Votes to transfer into	Ward Transfers needed
CON	8,460	3,408	0	5,052	Transfer in 32.0% (= 5052 / 15781) of ward's transfer pool votes
LAB	14,808	8,479	0	6,329	Transfer in 40.1% (= 6329 / 15781) of ward's transfer pool votes
LIB	5,105	1,859	0	3,246	Transfer in 20.6% (= 3246 / 15781) of ward's transfer pool votes
NAT	3,111	1,957	0	1,154	Transfer in 7.3% (= 1154 / 15781) of ward's transfer pool votes
OTH	1,447	17,229	15,782	0	Transfer away 91.6% (= 15782 / 17229) of ward's OTH votes
Total	32,931	32,932	15,781	15,781

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

New seat: Clwyd South

District	Ward	Electorate 2005	Old Seat	New Seat	CON Votes	LAB Votes	LIB Votes	NAT Votes	OTH Votes	Total Votes
Wrexham	Bronington	2,469	Clwyd South	Clwyd South	1,510	0	0	0	0	1,510
Wrexham	Brymbo	2,019	Clwyd South	Clwyd South	293	602	188	66	83	1,235
Wrexham	Bryn Cefn	1,477	Clwyd South	Clwyd South	129	624	82	29	36	903
Wrexham	Cefn	3,614	Clwyd South	Clwyd South	273	1,476	318	62	78	2,210
Wrexham	Chirk North	1,867	Clwyd South	Clwyd South	256	586	165	58	73	1,141
Wrexham	Chirk South	1,405	Clwyd South	Clwyd South	129	578	83	29	37	859
Wrexham	Coedpoeth	3,575	Clwyd South	Clwyd South	403	1,031	542	92	115	2,185
Denbighshire	Corwen	1,699	Clwyd South	Clwyd South	326	207	106	350	47	1,039
Wrexham	Dyffryn Ceiriog/Ceiriog Valley	1,740	Clwyd South	Clwyd South	219	275	141	365	62	1,064
Wrexham	Esclusham	2,000	Clwyd South	Clwyd South	260	660	167	59	74	1,222
Wrexham	Gwenfro	1,239	Clwyd South	Clwyd South	0	758	0	0	0	758
Wrexham	Johnstown	2,521	Clwyd South	Clwyd South	237	1,028	152	54	68	1,541
Denbighshire	Llandrillo	864	Clwyd South	Clwyd South	44	55	28	386	12	528
Wrexham	Llangollen Rural	1,527	Clwyd South	Clwyd South	219	458	141	50	62	933
Denbighshire	Llangollen	2,956	Clwyd South	Clwyd South	447	423	347	517	72	1,808
Wrexham	Marchwiel	1,870	Clwyd South	Clwyd South	302	491	194	69	86	1,144
Wrexham	Minera	1,923	Clwyd South	Clwyd South	170	807	109	39	48	1,176
Wrexham	New Broughton	2,474	Clwyd South	Clwyd South	247	979	159	56	70	1,513
Wrexham	Overton	2,344	Clwyd South	Clwyd South	1,433	0	0	0	0	1,433
Wrexham	Pant	1,642	Clwyd South	Clwyd South	202	567	130	46	57	1,004
Wrexham	Penycae and Ruabon South	1,812	Clwyd South	Clwyd South	242	585	155	55	69	1,108
Wrexham	Penycae	1,580	Clwyd South	Clwyd South	163	612	105	37	46	966
Wrexham	Plas Madoc	1,180	Clwyd South	Clwyd South	76	359	246	17	21	722
Wrexham	Ponciau	3,531	Clwyd South	Clwyd South	314	738	943	71	90	2,159
Wrexham	Ruabon	1,873	Clwyd South	Clwyd South	134	506	209	257	38	1,146
	Total			Clwyd South	8,039	14,416	4,719	2,773	1,357	31,306

And these are the implied results for 2005 for the new seat of Clwyd South.