AV vs STV

I've been asked on a facebook thread to blog on the differences between AV - being dangled as a carrot by both Labour and Conservatives before the Lib-Dems and STV, which is what the Lib-Dems actually favour.

AV or the Alternative Vote System is a majoritan system. The aim here is not for the number of seats to reflect proportionally the number of votes cast, but the winning candidate in each case to be supported by the majority of voters (even of they weren't the first choice for some).

The way it works is quite simple - we would keep the current constituencies and voters would rank all the candidates they wish to (leaving out ones they wouldn't want to vote for) from one downwards. Then all the first preferences are counted and if a candidate has over 50% of the vote, they are elected. If not, the lowest ranking candidate is eliminated and their votes re-allocated to second preference and so on until one candidate would have over 50%. This is roughly the system used for the London Mayoral elections.

What difference would it make and who wins? In reality, it would make not all that much difference. Last Thursday's results would have been different in about 20 seats - Tories losing out mainly to the Lib-Dems. (Which would move them both proportionally closer to their share of the vote, but still a long way off and Labour would have more seats when they already have far too many proportionally). It certainly makes life harder for the Tories - with not many other votes on the right they can pick up.

PROS:
- It eliminates the need for tactical voting
- It enables the elected members to claim a greater mandate
- It maintains constituency links for MPs

CONS:
- It makes it much harder for smaller parties to break through
- It re-enforces the problem of safe seats
- It does not reflect the votes cast proportionally or fix any of the real problems in the current system.


Single Transferrable Vote (STV) (as used in the last Scottish council elections) confusingly works in a similar way, in terms of ranking all the candidates you would vote for in order of preference. The difference being that it would work with larger multi-seat constituencies so the result is much more proportional. You would have several candidates from the main parties in each constituency and could choose between them (as opposed to the List system (as used in the European elections), where the party chooses their preferred candidates). The voting is actually very simple, as with AV, (this is not what caused the problems at the last Scottish elections), but the calculations become very complicated:

In a five seat constituency, a candidate would need about a fifth of the votes to be elected. If no candidate reaches this on first preference, then votes of the lowest candidate are re-assigned as with AV. Once a candidate has reached the required winning post, then the number of votes he has received over the required number are re-assigned proportionally to the second preferences of all the votes he has received. So, if somebody needs 1000 votes to be elected and gets 1200, then 200 votes are reallocated proportionally to the second preference of all 1200 votes.

PROs:
- It is a much more proportional system
- It gives a real opportunity to the smaller parties
- If there's a bad MP/candidate you don't like from a party you would otherwise support, you can still vote for the party in the shape of other candidates.
- Thus, there are no more safe seats, etc...
- The big parties get broader geographical representation, although less seats - for example would lead to more Conservative MPs from Scotland and North-East, but more Labour in the South-West and South-East than currently.

CONs:
- Will produce a hung parliament every time (argue amongst yourself whether thats good or bad)
- the calculations are very complicated, but most voters don't need to understand exactly how that works, as long as they understand how to vote.

An Edinburgh Example
In the 5 Edinburgh seats combined last week, the totals for the 4 main parties were:
Labour 82,623 votes (37%)
Lib-Dems 63,544 (29%)
Conservatives 42,682 (19%)
SNP 27,700 (12%)

The seats won were 4 for Labour and 1 Lib-Dem. Under AV I reckon the Lib-Dems would probably have taken Edinburgh South, but could well have lost Edinburgh West to Labour. Net result, no change.
Under STV the voting patterns would probably have been different, but I would guess the result would have been Alastair Darling and Mark Lazarowicz for Labour, Mike Crockart for the Lib-Dems, Jason Rust for the conservatives and then either Fred McKintosh (Lib-Dem) or one of the SNp candidates, which would have been a much fairer reflection of the votes cast.

If there were to be a referendum on AV, I'm not sure I would go for it, especially if it was put across as the final step in voting reform.