Electoral Reform
Select Country / Region
Majoritarian Systems
Input your expected vote shares for all parties to see how many seats they could win. This creates a complete constituency level projection.
Just make sure they sum to 100%.
For more info click here.
Electoral System
Choose between First Past the Post, the Alternative Vote, or the Supplementary Vote:
Preset Scenarios
Click a scenario to automatically fill the form with preset values:
Additional Member System (AMS)
Input your expected vote shares for all parties to see how many seats they could win. This creates a complete constituency level projection.
Just make sure they sum to 100%.
For more info click here.
Region Configuration
Choose how list seats are allocated:
Preset Scenarios
Click a scenario to automatically fill the form with preset values:
Single Transferable Vote (STV)
Input your expected vote shares for all parties to see how many seats they could win. This creates a complete constituency level projection.
Just make sure they sum to 100%.
For more info click here.
STV Configuration
Choose the STV region size:
Preset Scenarios
Click a scenario to automatically fill the form with preset values:
List Proportional Representation
Input your expected vote shares for all parties to see how many seats they could win. This creates a complete constituency level projection.
Just make sure they sum to 100%.
For more info click here.
List PR Configuration
Choose the region size:
Preset Scenarios
Click a scenario to automatically fill the form with preset values:
The options provided give an idea of what future electoral reform could look like. All are based on current constituency boundaries but with nearby constituencies combined in different ways to mimic PR systems currently used other countries.
The example systems provided are all based on the current electoral systems in use in other modern democracies. We measure the Gallagher Index for each result to show how close it is to the wishes of voters and the Effective Number of Parties to show how divided the results are.
The difference between Open and Closed Lists is not distinguished here. In the real world, Closed lists allow parties to pick the order of their candidates whilst Open lists let voters override the party's preferred order. This can change which person wins a seat, but not which party they are from.
There is no perfect way of undoing tactical voting, but we have taken some steps to do so. Regardless, PR systems are designed to create results which are reflective of the overall vote share so by changing the input you effectively override tactical voting overall, if not in each constituency.
England Voting Intention
Northern Ireland Voting Intention
Scotland Voting Intention
List Polls
Wales Voting Intention
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