Cynon Valley and Pontypridd: New Boundaries 2018 Calculation

Cynon Valley and Pontypridd: Overview

 Projection: LAB seat 

Implied MP at 2017: Ann Clwyd  (LAB)
County/Area: Mid Glamorgan (Wales)
Electorate: 83,057
Turnout: 63.4%

 Implied 2017 VotesImplied 2017 Share
LAB Majority19,02236.1%

See overview of other seats in Wales.

Cynon Valley and Pontypridd : Political and Demographic indicators

The table below shows some political and demographic numerical indicators for the new Cynon Valley and Pontypridd constituency, the 'Wales' area and nation.

The political measures include the three axes: Economic (Left/Right), National (Global/National) and Social (Liberal/Conservative). (what does this mean).

The demographic measures are from the 2011 Census and include categories relating to national identity, economic activity, health and education. These categories are those which have the most relevance to political attitudes.

IndicatorSeatWalesAll GB
Economic Position14° Left9° Left
National Position1° Glo
Social Position4° Lib2° Lib
EU Leave %54%52%52%
British Identity20%26%29%
Good Health45%47%48%
UK Born96%95%88%
Good Education32%36%39%
Good Job44%46%51%
High SEC41%46%51%
Average Age48.549.648.5
ABC1 Class43%47%53%

Cynon Valley and Pontypridd ranks #288 for "Leave", #526 for "Right", #389 for "National" and #464 for "Social" out of 600 new seats.

Indicators: Legend and Descriptions

Indicators : Legend and Descriptions

The colour scheme used in the table above is explained in the legend table below. The eight census indicators (British Identity, Good Health, UK Born, Good Education, Good Job, High SEC, Average Age and AB1 Class) all use the same 'Census' colour scheme indicating whether the area's level is above or below the national average.

TopicCat 1Cat 2Cat 3Cat 4Cat 5
Economic PositionVery LeftLeftCentristRightVery Right
National PositionVery GlobalGlobalCentristNationalVery Nat
Social PositionVery LibLiberalModerateConservativeVery Cons
EU Leave %Very RemainRemainBalancedLeaveVery Leave
CensusVery LowLowMediumHighVery High

Indicator definitions are given in terms of political data definitions or census categories:

Definition / Included Census Categories
Party WinnerArea party winner : actual election result or projected by Electoral Calculus
Economic PositionEconomic position between 100° Left and 100° Right, estimated by Electoral Calculus from political and demographic data.
National PositionNational position between 100° Global and 100° National, estimated by Electoral Calculus from political and demographic data.
Social PositionSocial position between 100° Liberal and 100° Conservative, estimated by Electoral Calculus from political and demographic data.
TribeTribe group dominant in the area. Can be: Strong Left, Traditionalists, Progressives, Centrists, Somewheres, Kind Young Capitalists, or Strong Right. See details.
EU Leave %EU Referendum vote share for 'Leave' : actual result or estimate
British IdentityNational Identity (KS202)Those answering British, British-Other, or Scottish-British
Good HealthHealth (KS301)Those answering 'Very Good Health'
UK BornCountry of Birth (QS203)Those answering England, Northern Ireland, Scotland, Wales, GB Other, or UK Other
Good EducationHighest level of Qualification (QS501)Level 3 (A-level equivalent) or Level 4+ (degree equivalent)
Good JobOccupation (QS606)Occupation codes 1xx to 4xx (Managers, Professionals, Associates, and office workers)
High SECNS-SeC of Household Reference Person (QS609)National Statistics Socio-economic Classification from 1 to 4 (higher managers and professionals, lower managers and professionals, intermediate occupations, small employers and self-employed).
Average AgeAge (QS103)Average age of adults (18 years and above)
ABC1 ClassApproximated Social Grade (QS611)Approximated social grades A, B and C1

Cynon Valley and Pontypridd: Map

Boundary Lines courtesy of Ordnance Survey OpenData © Crown copyright 2015


This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Cynon Valley and Pontypridd 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.

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.

More details of the calculation formulas are available.

List of old seats forming part of Cynon Valley and Pontypridd

The old seat(s) needed are:

Old seat: Cynon Valley

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

Old seat: Cynon ValleyTransfer-adjusted Results
New SeatCON
Rhondda Cynon TafAberaman North3,956Cynon Valley and Pontypridd4211,63441970259002,452
Rhondda Cynon TafAberaman South3,454Cynon Valley and Pontypridd3821,32621880322002,139
Rhondda Cynon TafAbercynon4,757Cynon Valley and Pontypridd5461,905771150304002,947
Rhondda Cynon TafAberdare East4,767Cynon Valley and Pontypridd5781,902481150310002,953
Rhondda Cynon TafAberdare West / Llwydcoed6,938Cynon Valley and Pontypridd9832,306541780778004,299
Rhondda Cynon TafCilfynydd2,100Cynon Valley and Pontypridd25579475490128001,301
Rhondda Cynon TafCwmbach3,281Cynon Valley and Pontypridd4271,17822810325002,033
Rhondda Cynon TafGlyncoch2,129Cynon Valley and Pontypridd15998823420108001,320
Rhondda Cynon TafHirwaun3,114Cynon Valley and Pontypridd43696625800422001,929
Rhondda Cynon TafMountain Ash East2,169Cynon Valley and Pontypridd29269222570280001,343
Rhondda Cynon TafMountain Ash West3,366Cynon Valley and Pontypridd3761,35426840245002,085
Rhondda Cynon TafPenrhiwceiber4,273Cynon Valley and Pontypridd4171,862301040234002,647
Rhondda Cynon TafPen-y-waun2,286Cynon Valley and Pontypridd23393115580180001,417
Rhondda Cynon TafRhigos1,267Cynon Valley and Pontypridd176431932013800786
Rhondda Cynon TafYnysybwl3,475Cynon Valley and Pontypridd4851,13698910343002,153
 Total51,332 6,16619,4055861,27104,3760031,804

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

Old seat: Pontypridd

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

Old seat: PontypriddTransfer-adjusted Results
New SeatCON
Rhondda Cynon TafBeddau3,140Rhondda and Llantrisant4801,28365480192002,068
Rhondda Cynon TafChurch Village3,794Cynon Valley and Pontypridd7111,38387550262002,498
Rhondda Cynon TafGraig (Pontypridd)1,855Cynon Valley and Pontypridd2657775629094001,221
Rhondda Cynon TafHawthorn2,699Cynon Valley and Pontypridd393970124460245001,778
Rhondda Cynon TafLlantrisant Town3,665Rhondda and Llantrisant6651,36571560257002,414
Rhondda Cynon TafLlantwit Fardre4,602Cynon Valley and Pontypridd1,3461,21586700314003,031
Rhondda Cynon TafPontypridd Town2,132Cynon Valley and Pontypridd403698124370142001,404
Rhondda Cynon TafRhondda3,510Cynon Valley and Pontypridd5541,42595600179002,313
Rhondda Cynon TafRhydfelen Central / Ilan3,370Cynon Valley and Pontypridd3851,533102460153002,219
Rhondda Cynon TafTaffs Well2,788Cardiff West4551,00467460266001,838
Rhondda Cynon TafTon-teg3,022Cynon Valley and Pontypridd6241,020164500132001,990
Rhondda Cynon TafTonyrefail East4,460Rhondda and Llantrisant7251,680168800284002,937
Rhondda Cynon TafTonyrefail West4,800Rhondda and Llantrisant7191,851100820408003,160
Rhondda Cynon TafTrallwng2,841Cynon Valley and Pontypridd489960223490151001,872
Rhondda Cynon TafTreforest3,900Cynon Valley and Pontypridd5751,547219570171002,569
Rhondda Cynon TafTyn-y-nant2,626Rhondda and Llantrisant3401,16351380137001,729
Rhondda Cynon TafLlanharry94Rhondda and Llantrisant153721070062
Rhondda Cynon TafPont-y-clun5,297Rhondda and Llantrisant1,1531,4391131860599003,490
Rhondda Cynon TafTalbot Green1,972Rhondda and Llantrisant35975445340108001,300
 Total60,567 10,65622,1041,9621,07004,1010039,893

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

New seat: Cynon Valley and Pontypridd

The new seat of Cynon Valley and Pontypridd is made up of the following wards, with the transfer-adjusted votes shown.

New seat: Cynon Valley and Pontypridd
Old Seat CON
Rhondda Cynon TafAberaman North3,956Cynon Valley4211,63441970259002,452
Rhondda Cynon TafAberaman South3,454Cynon Valley3821,32621880322002,139
Rhondda Cynon TafAbercynon4,757Cynon Valley5461,905771150304002,947
Rhondda Cynon TafAberdare East4,767Cynon Valley5781,902481150310002,953
Rhondda Cynon TafAberdare West / Llwydcoed6,938Cynon Valley9832,306541780778004,299
Rhondda Cynon TafChurch Village3,794Pontypridd7111,38387550262002,498
Rhondda Cynon TafCilfynydd2,100Cynon Valley25579475490128001,301
Rhondda Cynon TafCwmbach3,281Cynon Valley4271,17822810325002,033
Rhondda Cynon TafGlyncoch2,129Cynon Valley15998823420108001,320
Rhondda Cynon TafGraig (Pontypridd)1,855Pontypridd2657775629094001,221
Rhondda Cynon TafHawthorn2,699Pontypridd393970124460245001,778
Rhondda Cynon TafHirwaun3,114Cynon Valley43696625800422001,929
Rhondda Cynon TafLlantwit Fardre4,602Pontypridd1,3461,21586700314003,031
Rhondda Cynon TafMountain Ash East2,169Cynon Valley29269222570280001,343
Rhondda Cynon TafMountain Ash West3,366Cynon Valley3761,35426840245002,085
Rhondda Cynon TafPen-y-waun2,286Cynon Valley23393115580180001,417
Rhondda Cynon TafPenrhiwceiber4,273Cynon Valley4171,862301040234002,647
Rhondda Cynon TafPontypridd Town2,132Pontypridd403698124370142001,404
Rhondda Cynon TafRhigos1,267Cynon Valley176431932013800786
Rhondda Cynon TafRhondda3,510Pontypridd5541,42595600179002,313
Rhondda Cynon TafRhydfelen Central / Ilan3,370Pontypridd3851,533102460153002,219
Rhondda Cynon TafTon-Teg3,022Pontypridd6241,020164500132001,990
Rhondda Cynon TafTrallwng2,841Pontypridd489960223490151001,872
Rhondda Cynon TafTreforest3,900Pontypridd5751,547219570171002,569
Rhondda Cynon TafYnysybwl3,475Cynon Valley4851,13698910343002,153
 Total83,057 11,91130,9331,8661,77006,2190052,699

And these are the implied results for 2017 for the new seat of Cynon Valley and Pontypridd. Please note that the wards used are those of 2015 in order to be consistent with those used by the Boundary Commissions.

© 2019 Electoral Calculus Ltd
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