Lancashire West: New Boundaries Calculation

This page shows the detail of the calculations performed to estimate the general election result for 2005 had the new boundaries for Lancashire West 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 2005. 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.

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:

Old seat: Lancashire West

The main table shows the district council election results for all the wards in the old seat of Lancashire West. The first block shows the actual results, the second block shows the turnout-adjusted results, and the third block has the transfer-adjusted results. Details of the transfer calculation are given below this table.

 Actual ResultsTurnout-adjusted Results Transfer-adjusted Results
DistrictWardElectorate
2005		Old SeatNew Seat CON
Votes		LAB
Votes		LIB
Votes		OTH
Votes		CON
Votes		LAB
Votes		LIB
Votes		OTH
Votes		Total
Votes		CON
Votes		LAB
Votes		LIB
Votes		OTH
Votes		Total
Votes
West LancashireAshurst4,896Lancashire WestLancashire West33091103475921,63606232,8516221,7971832472,851
West LancashireAughton and Downholland4,626Lancashire WestLancashire West1,725503002,086608002,6942,086608002,694
West LancashireAughton Park3,139Lancashire WestLancashire West00000000000000
West LancashireBickerstaffe1,678Lancashire WestLancashire West00000000000000
West LancashireBirch Green3,090Lancashire WestLancashire West159676003431,457001,8003431,457001,800
West LancashireBurscough East3,188Lancashire WestLancashire West900584001,126731001,8571,126731001,857
West LancashireBurscough West3,932Lancashire WestLancashire West763832001,0951,194002,2891,0951,194002,289
West LancashireDerby4,580Lancashire WestLancashire West9875501904441,2126762335452,6661,2398173932162,666
West LancashireDigmoor3,204Lancashire WestLancashire West11771001472241,36002821,8662381,433821111,866
West LancashireHalsall1,803Lancashire WestLancashire West45900370581004691,0506041211371851,050
West LancashireKnowsley4,614Lancashire WestLancashire West1,36065202041,64979002472,6861,66185472972,686
West LancashireMoorside2,866Lancashire WestLancashire West143664002961,373001,6692961,373001,669
West LancashireNewburgh1,718Lancashire WestLancashire West00000000000000
West LancashireParbold3,191Lancashire WestLancashire West00000000000000
West LancashireScarisbrick3,047Lancashire WestLancashire West00000000000000
West LancashireScott4,610Lancashire WestLancashire West1,04482003051,2921,01503772,6841,3101,1121101492,684
West LancashireSkelmersdale North3,163Lancashire WestLancashire West157531047324984207501,8412861,0362202971,841
West LancashireSkelmersdale South5,031Lancashire WestLancashire West3341,07702825781,86404882,9306021,9901431932,930
West LancashireTanhouse3,346Lancashire WestLancashire West00000000000000
West LancashireUp Holland4,954Lancashire WestLancashire West7871,06603661,0231,38604762,8851,0461,5091391882,885
West LancashireWrightington3,436Lancashire WestLancashire West1,184595001,332669002,0011,332669002,001
 Total Lancashire West     13,67815,6012334,25733,76913,88916,7061,4841,68733,769

The transfer table below shows the votes cast in the old seat of Lancashire West 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.

PartyGeneral
Election 2005
Votes		Local Election
Turnout-adjusted
Votes 		Votes to
transfer
away		Votes to
transfer
into		Ward Transfers needed
CON14,66213,6780984Transfer in 8.2% (= 984 / 11955) of ward's transfer pool votes
LAB20,74615,60105,145Transfer in 43.0% (= 5145 / 11955) of ward's transfer pool votes
LIB6,05923305,826Transfer in 48.7% (= 5826 / 11955) of ward's transfer pool votes
OTH1,6884,2572,5690Transfer away 60.3% (= 2569 / 4257) of ward's OTH votes
Total43,15533,76911,95511,955 

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

New seat: Lancashire West

The new seat of Lancashire West is made up of the following wards, with the transfer-adjusted votes shown.

DistrictWardElectorate
2005		Old SeatNew Seat CON
Votes		LAB
Votes		LIB
Votes		OTH
Votes		Total
Votes
West LancashireAshurst4,896Lancashire WestLancashire West6221,7971832472,851
West LancashireAughton Park3,139Lancashire WestLancashire West00000
West LancashireAughton and Downholland4,626Lancashire WestLancashire West2,086608002,694
West LancashireBickerstaffe1,678Lancashire WestLancashire West00000
West LancashireBirch Green3,090Lancashire WestLancashire West3431,457001,800
West LancashireBurscough East3,188Lancashire WestLancashire West1,126731001,857
West LancashireBurscough West3,932Lancashire WestLancashire West1,0951,194002,289
West LancashireDerby4,580Lancashire WestLancashire West1,2398173932162,666
West LancashireDigmoor3,204Lancashire WestLancashire West2381,433821111,866
West LancashireHalsall1,803Lancashire WestLancashire West6041211371851,050
West LancashireKnowsley4,614Lancashire WestLancashire West1,66185472972,686
West LancashireMoorside2,866Lancashire WestLancashire West2961,373001,669
West LancashireNewburgh1,718Lancashire WestLancashire West00000
West LancashireParbold3,191Lancashire WestLancashire West00000
West LancashireScarisbrick3,047Lancashire WestLancashire West00000
West LancashireScott4,610Lancashire WestLancashire West1,3101,1121101492,684
West LancashireSkelmersdale North3,163Lancashire WestLancashire West2861,0362202971,841
West LancashireSkelmersdale South5,031Lancashire WestLancashire West6021,9901431932,930
West LancashireTanhouse3,346Lancashire WestLancashire West00000
West LancashireUp Holland4,954Lancashire WestLancashire West1,0461,5091391882,885
West LancashireWrightington3,436Lancashire WestLancashire West1,332669002,001
 Total  Lancashire West13,88916,7061,4841,68733,768

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.