Merthyr Tydfil And Rhymney: 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:

• Merthyr Tydfil and Rhymney

Old seat: Merthyr Tydfil and Rhymney

					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
Caerphilly	Darren Valley	1,901	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	505	0	172	0	0	766	0	261	0	1,027	0	766	0	261	0	1,027
Caerphilly	Moriah	3,414	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	1,731	0	273	0	0	1,593	0	251	0	1,844	0	1,593	0	251	0	1,844
Caerphilly	New Tredegar	3,700	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	2,011	0	326	0	0	1,720	0	279	0	1,999	0	1,720	0	279	0	1,999
Caerphilly	Pontlottyn	1,474	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	410	0	103	0	0	637	0	160	0	797	0	637	0	160	0	797
Caerphilly	Twyn Carno	1,841	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	220	0	0	492	0	307	0	0	687	994	0	307	0	0	687	994
Merthyr Tydfil	Bedlinog	2,632	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Cyfarthfa	4,714	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Dowlais	5,106	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Gurnos	3,681	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Merthyr Vale	2,930	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Park	3,483	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Penydarren	3,968	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Plymouth	3,850	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Town	5,259	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Treharris	4,757	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Merthyr Tydfil	Vaynor	2,766	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Total		Merthyr Tydfil and Rhymney							0	5,023	0	951	687	6,661	0	5,023	0	951	687	6,661

The transfer table below shows the votes cast in the old seat of Merthyr Tydfil and Rhymney 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	2,680	0	0	2,680	Transfer in 11.5% (= 2680 / 23315) of ward's transfer pool votes
LAB	18,129	5,023	0	13,106	Transfer in 56.2% (= 13106 / 23315) of ward's transfer pool votes
LIB	4,195	0	0	4,195	Transfer in 18.0% (= 4195 / 23315) of ward's transfer pool votes
NAT	2,972	951	0	2,021	Transfer in 8.7% (= 2021 / 23315) of ward's transfer pool votes
OTH	2,000	687	0	1,313	Transfer in 5.6% (= 1313 / 23315) of ward's transfer pool votes
Total	29,976	6,661	23,315	23,315

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

New seat: Merthyr Tydfil And Rhymney

District	Ward	Electorate 2005	Old Seat	New Seat	CON Votes	LAB Votes	LIB Votes	NAT Votes	OTH Votes	Total Votes
Merthyr Tydfil	Bedlinog	2,632	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Cyfarthfa	4,714	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Caerphilly	Darren Valley	1,901	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	766	0	261	0	1,027
Merthyr Tydfil	Dowlais	5,106	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Gurnos	3,681	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Merthyr Vale	2,930	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Caerphilly	Moriah	3,414	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	1,593	0	251	0	1,844
Caerphilly	New Tredegar	3,700	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	1,720	0	279	0	1,999
Merthyr Tydfil	Park	3,483	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Penydarren	3,968	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Plymouth	3,850	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Caerphilly	Pontlottyn	1,474	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	637	0	160	0	797
Merthyr Tydfil	Town	5,259	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Merthyr Tydfil	Treharris	4,757	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
Caerphilly	Twyn Carno	1,841	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	307	0	0	687	994
Merthyr Tydfil	Vaynor	2,766	Merthyr Tydfil and Rhymney	Merthyr Tydfil And Rhymney	0	0	0	0	0	0
	Total			Merthyr Tydfil And Rhymney	0	5,023	0	951	687	6,661

This seat was actually unchanged by the Boundary Commission, so these calculations are shown for information only. The actual general election result for 2005 should be used for this seat.