Scotland's voting system is far better than Westminster's, but this election shows change is needed
By Richard Wood, Council member at Unlock Democracy. The views expressed do not necessarily reflect those of Unlock Democracy.
Elections to the Scottish Parliament are regularly highlighted by democracy campaigners as a viable alternative to Westminster's indefensible First Past the Post system. But after last month’s produced Scotland's least ever proportional election, changes are needed north of the border too.
The Scottish Parliament uses the Additional Member System to elect MSPs where voters get two ballots, one for their First Past the Post local constituency MSP and one for regional lists. 73 MSPs win their seats just like in Westminster elections, but an additional 56 MSPs are allocated from the regional list vote, taking into account seats won constituency seats won by each party to ensure broadly proportional results overall.
Until 2026, voters in Scotland got six parliaments where the proportion of seats won by each party roughly reflected how people voted. The system has never been perfectly proportional, with the once dominant Scottish Labour winning more seats than it would be entitled if all seats were allocated proportionally, which is the outcome AMS is ideally intended to produce. But the 2026 election blows those results out of the water showing that the system needs fixed.
This time the SNP won 58 out of 129 seats on 27.2% of the list vote and 38.2% of the constituency vote. With 58 out of the 129 available amounting to 45% of the seats at Holyrood, the system is not producing proportional outcomes as intended.
Of course, had Scotland only used the First Past the Post element, the SNP would have won a staggering 78% of seats. The list seats are doing their job to limit the disproportionality seen at Westminster, but they have fallen short to produce a truly proportional outcome.
The Additional Member System no longer works as intended
So, in a system designed to be proportional, how has this happened?
Simply put, since the Scottish Parliament has more First Past the Post seats than list seats, there is always the risk that the former can skew proportional outcomes. The SNP have done well to win the vast majority of constituency seats but on a relatively low vote share, benefitting from a divided opposition and the Scottish Greens only standing in six constituencies, as well as split-ticket voting. The regional list element corrects overrepresentation to an extent but is limited by the fixed number of list seats available.
The extent of the SNP's overrepresentation can be measured by overhangs, which are the difference between the actual number of seats won by a party and the number of seats it would be entitled to if all seats were determined by list votes alone. This is the ideal AMS outcome, and is shown well by New Zealand’s similar mixed system where list seat shares closely match list votes). In 2026, the SNP won 18 overhang seats, according to analysis by Ballot Box Scotland — that's far more than the number of overhangs won by any party in previous Scottish elections.
Another measure of proportionality is the Gallagher Index, which allows us to compare between elections. While the index for Scottish elections is usually between 5 and 10 (sitting in the broadly proportional range), this time the figure jumped to 13.7.
The 2026 election therefore highlights a flaw of the Additional Member System, driven by the First Past the Post element, that needs to be addressed.
Reforming the Scottish Parliament
In a democratic country, seats should match votes. Proportionality is a fundamental democratic principle, one that was recognised by Scotland's Constitutional Convention, which led to the establishment of the Scottish Parliament in 1999. But the 2026 election has given a result that is diverging from this design principle.
Furthermore, the Convention wanted the voting system to put the greatest “the greatest possible power in the hands of the electorate”. And rightly so. But with such an unrepresentative result, not to mention shortfalls in this area concerning limited voter power over individual candidates in closed party lists, there is scope within the principles of the Constitutional Convention for reforming Scotland’s voting system.
To change the voting system at Holyrood, two-thirds of MSPs must back reform. A number of options are available including modifying the current system, adopting the Single Transferable Vote (which if designed well would improve proportionality and improve voter choice) or something more radical like open list PR with levelling seats.
Whatever the outcome, Scotland's politicians must find consensus to unlock Scotland's democratic potential.