New Seat Details - Perth and North Perthshire

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Perth and North Perthshire 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
CON	22,652	42.4%
SNP	22,599	42.3%
LAB	5,549	10.4%
LIB	2,643	4.9%
CON Majority	53	0.1%

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.

Perth and North Perthshire: Map

List of old seats forming part of Perth and North Perthshire

Old seat: Ochil and South Perthshire

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

Old seat: Ochil and South Perthshire				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	SNP Votes	MIN Votes	OTH Votes	Total Votes
Clackmannanshire	Clackmannanshire Central	6,005	Clackmannanshire and Dunfermline	1,385	1,447	90	0	0	1,525	0	0	4,447
Clackmannanshire	Clackmannanshire East	5,599	Clackmannanshire and Dunfermline	1,717	851	65	0	0	1,304	0	0	3,937
Clackmannanshire	Clackmannanshire North	8,157	Clackmannanshire and Dunfermline	1,986	1,442	180	0	0	2,273	0	0	5,881
Clackmannanshire	Clackmannanshire South	9,139	Clackmannanshire and Dunfermline	2,000	2,087	145	0	0	2,511	0	0	6,743
Clackmannanshire	Clackmannanshire West	8,265	Clackmannanshire and Dunfermline	2,261	2,109	145	0	0	2,253	0	0	6,768
Perth and Kinross	Almond and Earn	8,784	Stirlingshire, Strathearn and Kinross	3,095	657	232	0	0	2,315	0	0	6,299
Perth and Kinross	Kinross-shire	9,975	Stirlingshire, Strathearn and Kinross	3,382	784	413	0	0	2,259	0	0	6,838
Perth and Kinross	Strathallan	7,830	Stirlingshire, Strathearn and Kinross	2,686	583	237	0	0	1,885	0	0	5,391
Perth and Kinross	Strathearn	8,066	Stirlingshire, Strathearn and Kinross	3,087	687	179	0	0	1,989	0	0	5,942
Perth and Kinross	Strathtay	2,874	Perth and North Perthshire	871	200	55	0	0	795	0	0	1,921
	Total	74,694		22,470	10,847	1,741	0	0	19,109	0	0	54,167

The full details of these calculations are given on the Ochil and South Perthshire seat details page. Click on "Show workings".

Old seat: Perth and North Perthshire

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

Old seat: Perth and North Perthshire				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	SNP Votes	MIN Votes	OTH Votes	Total Votes
Perth and Kinross	Blairgowrie and Glens	8,179	Perth and North Perthshire	2,608	388	158	0	0	2,658	0	0	5,812
Perth and Kinross	Carse of Gowrie	7,512	Perth and North Perthshire	2,520	395	172	0	0	2,083	0	0	5,170
Perth and Kinross	Highland	6,820	Perth and North Perthshire	2,089	222	192	0	0	2,380	0	0	4,883
Perth and Kinross	Perth City Centre	10,074	Perth and North Perthshire	3,236	1,267	555	0	0	3,267	0	0	8,325
Perth and Kinross	Perth City North	10,801	Perth and North Perthshire	2,846	1,794	379	0	0	3,984	0	0	9,003
Perth and Kinross	Perth City South	10,779	Perth and North Perthshire	3,484	653	593	0	0	2,750	0	0	7,480
Perth and Kinross	Strathmore	11,498	Perth and North Perthshire	3,597	459	448	0	0	3,307	0	0	7,811
Perth and Kinross	Strathtay	4,285	Perth and North Perthshire	1,401	171	91	0	0	1,375	0	0	3,038
	Total	69,948		21,781	5,349	2,588	0	0	21,804	0	0	51,522

The full details of these calculations are given on the Perth and North Perthshire seat details page. Click on "Show workings".

New seat: Perth and North Perthshire

District	Ward	Electorate 2017	Old Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	SNP Votes	MIN Votes	OTH Votes	Total Votes
New seat: Perth and North Perthshire
Perth and Kinross	Blairgowrie and Glens	8,093	Perth and North Perthshire	2,608	388	158	0	0	2,658	0	0	5,812
Perth and Kinross	Carse of Gowrie	7,199	Perth and North Perthshire	2,520	395	172	0	0	2,083	0	0	5,170
Perth and Kinross	Highland	6,798	Perth and North Perthshire	2,089	222	192	0	0	2,380	0	0	4,883
Perth and Kinross	Perth City Centre	11,591	Perth and North Perthshire	3,236	1,267	555	0	0	3,267	0	0	8,325
Perth and Kinross	Perth City North	12,537	Perth and North Perthshire	2,846	1,794	379	0	0	3,984	0	0	9,003
Perth and Kinross	Perth City South	10,416	Perth and North Perthshire	3,484	653	593	0	0	2,750	0	0	7,480
Perth and Kinross	Strathmore	10,876	Perth and North Perthshire	3,597	459	448	0	0	3,307	0	0	7,811
Perth and Kinross	Strathtay	2,724	Ochil and South Perthshire	871	200	55	0	0	795	0	0	1,921
Perth and Kinross	Strathtay	4,232	Perth and North Perthshire	1,401	171	91	0	0	1,375	0	0	3,038
	Total	74,466		22,652	5,549	2,643	0	0	22,599	0	0	53,443

And these are the implied results for 2017 for the new seat of Perth and North Perthshire. 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:	Unknown (changed seat) (CON)
County/Area:	Tayside (Scotland)
Electorate:	74,466
Turnout:	71.8%

Perth and North Perthshire: New Boundaries 2018 Calculation

Perth and North Perthshire: Overview

Introduction