Rev. 15 Feb 26
I am now thinking about, working towards, and have started to write about STVAMS, which looks to become my absolute top preference.
STVAMS is progressive STV with integrated TopUp-lite.
Progressive STV is PV (single-seat ORCV) progressively and selectively converted into STV in places where towns or counties have been artificially split and where recombination is convenient and locally acceptable.
TopUp-lite is concerned not with establishing proportionality but with reducing blatant and offensive disproportionality. It would tend to regard (say) 10% as a top-up norm rather than e.g. the OTT 43% Scotland has.
It would be regionally based. (England has 9 identified regions; eeach of the 3 devolved nations would be a single region.)
There would be no separate top-up ballot (as required by orthodox AMS) but just the totalling of first-choice votes across all constituencies in the region.
The allocation of top-up seats would be by the same D’Hondt-based calculation used in orthodox AMS. And the allocation would be to parties identified in the constituencies ballots, except that (a) any group of parties can ask to be treated as a unit for top-up purposes, and (b) independent candidates are treated as a single group.
Each group’s top-up seats are allocated to the best performing losing candidates in the group. We need to agree a sufficiently hardy, realistic, appropriate, and comprehensible, formula for “best performing”. A good candidate would be just the highest number of votes finally allocated to that candidate (i.e. after all transfers in). But possibly, to make approporiate provision for multi-seat constituencies, that highest final vote as a percentage of (a) notional constituency size, or (b) total votes cast, or (c) final votes allocated to the last winning candidate.
For me, what make this approach the unassailable winner is a unique feature that came in by accident rather than as part of the original design: it makes provision for a top-up of independents, who are indisputably the most disproportionately under-represented group of all. 🙂