The Additional Member System Plus (AMS+)

The Additional Member System has been successfully used in Scotland and Wales since devolution. AMS+ is an improved version that keeps everything you know about AMS—two votes, proportional results, local representation—while making constituency voting more expressive through approval voting.

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Why AMS+?

🗳️ Greater Expression

Approve multiple candidates you trust to represent your constituency, rather than being forced into a single choice.

🎯 No Spoiler Effect

Support your favorite candidates without worrying about splitting the vote or letting your least-preferred candidate win.

⚖️ Proportional Results

The party list ensures overall proportional representation while local seats reflect broad community support.

🤝 Encourages Consensus

Candidates who appeal across different groups are rewarded, promoting coalition-building and moderation.

📊 Better Accountability

Dual accountability through both local approval and party proportionality creates stronger democratic incentives.

🔄 Familiar Structure

Builds on the proven AMS system already used in Scotland and Wales with minimal disruption.

How You Vote

How It Works

Cast Your Votes

Approve multiple constituency candidates and select one party for the regional list

Count Approvals

The constituency candidate with the most approvals wins the local seat

Allocate List Seats

Regional list seats are distributed proportionally based on party vote share

Balanced Representation

Final assembly reflects both local approval and proportional party support

AMS+ vs Traditional Systems

Better than First Past the Post

Proportional overall results
No wasted votes
Every vote counts toward representation
Eliminates tactical voting pressure

Improves on Traditional AMS

More expressive constituency voting
Reduces vote splitting
Rewards consensus candidates
Maintains familiar two-vote structure

Real Democratic Choice

Support all acceptable candidates
Honest preference expression
Strong local-national balance
Clear, understandable ballots

The Foundation: AMS in Scotland and Wales

The Additional Member System isn't theoretical. It's been successfully used for elections in Scotland and Wales since 1999, proving it works in practice across the UK.

🏴󠁧󠁢󠁳󠁣󠁴󠁿 Scotland

Scottish Parliament elections use AMS with 129 seats: 73 from constituencies (first-past-the-post) and 56 from regional lists (proportional). Voters are familiar with the two-vote system.

🏴󠁧󠁢󠁷󠁬󠁳󠁿 Wales

Welsh Senedd elections use the same AMS system with 60 seats: 40 from constituencies and 20 from regional lists. It's been delivering proportional representation for over two decades.

✅ Proven Track Record

Over 25 years of successful elections, high voter turnout, and stable coalition governments demonstrate AMS works. AMS+ simply improves it by giving voters more choice in their local vote.

Common Questions

Won't approval voting in constituencies be confusing?

No. Voters already approve multiple candidates at local council elections. The instruction is simple: "Tick all candidates you'd be happy with." The winner is whoever gets the most approvals. Much clearer than ranking candidates or complex preference systems.

Won't this take longer to count?

Approval voting is faster to count than ranking systems. You simply add up the ticks for each candidate—no complex transfers or calculations. The party list results (already familiar from Scotland and Wales) also count quickly.

How does approval voting stop tactical voting?

With approval voting, you don't need to worry about "wasting" your vote by supporting a less popular candidate. You vote honestly for all candidates you support. If your favourite doesn't have enough support, your approval still goes to others you chose.

What if I don't want to approve anyone?

That's fine. You can approve as few or as many candidates as you like—even just one, if that's what you prefer. AMS+ gives you choice. Some voters might approve three candidates, others just one.

Will this work across the whole UK?

Yes. AMS already works across the UK with regional variations. AMS+ would work the same way—each region would have its own constituencies and list system, just like current Scottish and Welsh elections.

Is this just proportional representation under a different name?

No. AMS+ keeps the two-vote system where your local vote stays local and your party vote is used proportionally across the region. This balance between local accountability and proportional fairness is what makes it effective.

What's the Difference Between AMS and MMP?

AMS (Additional Member System) and MMP (Mixed Member Proportional) are related hybrid systems that combine local constituency representation with proportional party lists, but they differ in how proportionality is achieved:

AMS: A system where voters have two separate votes - one for a constituency candidate and one for a party list. The list seats are allocated to "top-up" the constituency results to achieve proportionality. However, AMS may not guarantee full proportionality because list seats are allocated regionally and may not fully compensate for disproportionality in constituency results.
MMP: A system where voters have two votes - one for a constituency candidate and one for a party list. The list seats are allocated to achieve overall proportionality based on the party list vote. MMP ensures that the final seat distribution matches the party list vote share, making it truly proportional.

Both AMS and MMP Work Better with Approval Voting: Both AMS and MMP can be significantly improved by using approval voting rather than "choose one" for the constituency vote. With approval voting, voters can approve multiple candidates, allowing them to express support for their preferred candidate while also approving other acceptable candidates. This eliminates tactical voting in constituencies and ensures that constituency winners have broader support than what "choose one" voting typically produces.

Under traditional AMS and MMP, voters must choose a single constituency candidate, which can lead to tactical voting where voters abandon their true preference to avoid wasting their vote. Approval voting solves this by allowing voters to support multiple candidates they find acceptable. This means constituency winners are more likely to have genuine broad support rather than winning with a plurality from a split opposition. Combined with the proportional party list vote, this creates a system where both local representation and overall proportionality are achieved through voting methods that better reflect voter preferences.

What Apportionment Method Does AMS Use?

The Additional Member System uses the D'Hondt method for allocating party list seats. This method divides each party's vote total by a series of divisors (1, 2, 3, 4, 5...) to calculate quotients, and seats are allocated to the parties with the highest quotients.

D'Hondt is used in Scotland and Wales for their AMS elections. It tends to favor larger parties slightly compared to alternative methods like Sainte-Laguë (which uses divisors 1, 3, 5, 7, 9...). However, D'Hondt is straightforward to calculate and understand, making it practical for electoral administration.

The method works by calculating quotients for each party at each seat allocation round. For example, if a party has 100,000 votes, its quotients would be 100,000 (÷1), 50,000 (÷2), 33,333 (÷3), and so on. The seats go to whichever parties have the highest quotients after accounting for constituency seats already won.

How Does AMS+ Compare with STV?

STV (Single Transferable Vote) is a proportional voting system that uses ranked choice voting in multi-member constituencies. Here's how AMS+ compares:

Simplicity: AMS+ uses simple approval voting (tick all acceptable candidates) and a single party vote. STV requires voters to rank candidates in order of preference, which can be confusing and error-prone.
Counting Speed: AMS+ results can be counted quickly on election night. Approval voting is simply adding up ticks, and party list allocation is straightforward. STV requires complex transfer calculations that can take days to complete.
Local Representation: AMS+ maintains single-member constituencies for local accountability, combined with regional party lists for proportionality. STV uses larger multi-member constituencies, which can dilute local representation.
Voter Understanding: AMS+ builds on the familiar two-vote system already used in Scotland and Wales. STV's ranking system is less familiar to UK voters and requires more explanation.
Error Rates: Approval voting ballots have lower error rates than ranked ballots, where voters may accidentally skip rankings or duplicate numbers.
Proportionality: Both systems achieve proportional results, but AMS+ does so through a simpler mechanism that voters already understand from Scottish and Welsh elections.

AMS+ provides the benefits of proportional representation while maintaining simplicity and familiarity. It avoids the complexity and counting delays associated with STV while delivering similar proportional outcomes.

🎯 The Bottom Line

AMS+ builds on the proven success of the Additional Member System used in Scotland and Wales, but with a crucial improvement: approval voting for constituency seats. This combination delivers proportional representation with local accountability while giving voters genuine choice and expression.

Remember: With AMS+, you're not forced to choose just one candidate—you approve all the candidates you trust, creating a more representative and responsive democracy.