New Seat Details

This page shows the detail of the calculations performed to estimate the general election result for 2017 had the new boundaries for Watford 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	23,832	43.9%
LAB	23,674	43.6%
LIB	4,836	8.9%
UKIP	1,212	2.2%
Green	743	1.4%
CON Majority	158	0.3%

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.

Watford: Map

List of old seats forming part of Watford

Old seat: Hertfordshire South West

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

Old seat: Hertfordshire South West				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
Dacorum	Aldbury and Wigginton	1,839	Hertfordshire South West	813	308	198	16	59	0	0	0	1,394
Dacorum	Berkhamsted Castle	4,548	Hertfordshire South West	1,995	724	488	41	146	0	0	0	3,394
Dacorum	Berkhamsted East	4,368	Hertfordshire South West	1,818	985	495	39	153	0	0	0	3,490
Dacorum	Berkhamsted West	4,411	Hertfordshire South West	2,043	930	333	38	143	0	0	0	3,487
Dacorum	Bovingdon, Flaunden and Chipperfield	6,276	Hertfordshire South West	3,620	968	348	67	197	0	0	0	5,200
Dacorum	Northchurch	2,127	Hertfordshire South West	1,017	362	146	22	65	0	0	0	1,612
Dacorum	Tring Central	3,822	Hertfordshire South West	1,670	763	430	42	128	0	0	0	3,033
Dacorum	Tring East	2,149	Hertfordshire South West	1,020	375	229	47	31	0	0	0	1,702
Dacorum	Tring West and Rural	4,017	Hertfordshire South West	1,624	752	448	91	130	0	0	0	3,045
Three Rivers	Carpenders Park	1,383	Watford	558	333	102	36	16	0	0	0	1,045
Three Rivers	Chorleywood North and Sarratt	5,848	Hertfordshire South West	2,924	676	252	99	51	0	0	0	4,002
Three Rivers	Chorleywood South and Maple Cross	5,728	Hertfordshire South West	2,619	1,002	664	55	71	0	0	0	4,411
Three Rivers	Dickinsons	5,147	Hertfordshire South West	1,963	1,000	590	113	65	0	0	0	3,731
Three Rivers	Durrants	5,026	Hertfordshire South West	1,812	937	580	118	56	0	0	0	3,503
Three Rivers	Moor Park and Eastbury	4,571	Hertfordshire South West	2,530	525	196	17	39	0	0	0	3,307
Three Rivers	Oxhey Hall and Hayling	2,589	Watford	998	771	256	69	33	0	0	0	2,127
Three Rivers	Penn and Mill End	5,063	Hertfordshire South West	2,082	1,197	608	129	59	0	0	0	4,075
Three Rivers	Rickmansworth Town	5,369	Hertfordshire South West	2,378	990	429	107	67	0	0	0	3,971
Three Rivers	South Oxhey	4,537	Watford	1,643	1,978	286	147	68	0	0	0	4,122
	Total	78,818		35,127	15,576	7,078	1,293	1,577	0	0	0	60,651

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

Old seat: Watford

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

Old seat: Watford				Transfer-adjusted Results
District	Ward	Electorate 2017	New Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
Three Rivers	Abbots Langley and Bedmond	3,892	St Albans	1,456	840	258	31	16	0	0	0	2,601
Three Rivers	Carpenders Park	3,623	Watford	1,377	869	176	63	12	0	0	0	2,497
Three Rivers	Gade Valley	2,958	Hemel Hempstead	1,168	681	187	24	11	0	0	0	2,071
Three Rivers	Leavesden	5,111	St Albans	1,750	1,186	350	83	19	0	0	0	3,388
Three Rivers	Oxhey Hall and Hayling	2,268	Watford	834	658	162	40	10	0	0	0	1,704
Watford	Callowland	4,815	Watford	1,454	1,908	312	89	60	0	0	0	3,823
Watford	Central	5,543	Watford	1,492	2,100	436	94	66	0	0	0	4,188
Watford	Holywell	5,624	Watford	1,473	2,587	248	84	56	0	0	0	4,448
Watford	Leggatts	5,518	Watford	1,653	1,833	230	82	48	0	0	0	3,846
Watford	Meriden	5,679	Watford	1,777	1,720	394	97	48	0	0	0	4,036
Watford	Nascot	6,002	Watford	2,076	1,329	375	78	54	0	0	0	3,912
Watford	Oxhey	5,054	Watford	1,596	1,330	462	40	64	0	0	0	3,492
Watford	Park	5,699	Watford	2,113	1,344	389	75	54	0	0	0	3,975
Watford	Stanborough	5,189	Watford	1,810	1,371	401	68	47	0	0	0	3,697
Watford	Tudor	4,430	Watford	1,614	1,097	315	67	42	0	0	0	3,135
Watford	Vicarage	4,698	Watford	1,364	2,446	292	83	65	0	0	0	4,250
Watford	Woodside	5,233	St Albans	1,726	1,338	347	86	47	0	0	0	3,544
	Total	81,336		26,733	24,637	5,334	1,184	719	0	0	0	58,607

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

New seat: Watford

District	Ward	Electorate 2017	Old Seat	CON Votes	LAB Votes	LIB Votes	UKIP Votes	Green Votes	NAT Votes	MIN Votes	OTH Votes	Total Votes
New seat: Watford
Three Rivers	Carpenders Park	1,382	Hertfordshire South West	558	333	102	36	16	0	0	0	1,045
Three Rivers	Carpenders Park	3,687	Watford	1,377	869	176	63	12	0	0	0	2,497
Three Rivers	Oxhey Hall and Hayling	2,817	Hertfordshire South West	998	771	256	69	33	0	0	0	2,127
Three Rivers	Oxhey Hall and Hayling	2,514	Watford	834	658	162	40	10	0	0	0	1,704
Three Rivers	South Oxhey	5,457	Hertfordshire South West	1,643	1,978	286	147	68	0	0	0	4,122
Watford	Callowland	5,642	Watford	1,454	1,908	312	89	60	0	0	0	3,823
Watford	Central	6,181	Watford	1,492	2,100	436	94	66	0	0	0	4,188
Watford	Holywell	6,564	Watford	1,473	2,587	248	84	56	0	0	0	4,448
Watford	Leggatts	5,677	Watford	1,653	1,833	230	82	48	0	0	0	3,846
Watford	Meriden	5,957	Watford	1,777	1,720	394	97	48	0	0	0	4,036
Watford	Nascot	5,775	Watford	2,076	1,329	375	78	54	0	0	0	3,912
Watford	Oxhey	5,154	Watford	1,596	1,330	462	40	64	0	0	0	3,492
Watford	Park	5,867	Watford	2,113	1,344	389	75	54	0	0	0	3,975
Watford	Stanborough	5,457	Watford	1,810	1,371	401	68	47	0	0	0	3,697
Watford	Tudor	4,627	Watford	1,614	1,097	315	67	42	0	0	0	3,135
Watford	Vicarage	6,273	Watford	1,364	2,446	292	83	65	0	0	0	4,250
	Total	79,031		23,832	23,674	4,836	1,212	743	0	0	0	54,297

And these are the implied results for 2017 for the new seat of Watford. 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:	Richard Harrington (CON)
County/Area:	Hertfordshire (Anglia)
Electorate:	79,031
Turnout:	68.7%

Watford: New Boundaries 2018 Calculation

Watford: Overview

Introduction