AMS – It’s Not That Hard

There’s a wee habit that the Scottish media has that really niggles away at me. In an era of “fake news” and widespread distrust of the “mainstream media”, there are worse problems with journalism and the public’s relationship with it. Nonetheless, this little thing bugs the big part of me that’s an elections nerd. Can the media, for the love of goodness, stop referring to AMS as “complex”?

Whenever a journalist talks about the Scottish Parliament electoral system, it’s pretty much guaranteed they will describe it as “complex”. On one level, I can understand why – for all that we use PR widely in Scotland, political discourse in the UK is still wedded to First Past the Post. The presence of proportional representation outside of Northern Ireland only dates to 1999. UK General Elections, widely viewed even now as the “most important” still use FPTP. And in Scotland, we use a different electoral system for every election we have, albeit one is effectively the combined form of two of the others. A certain level of puzzlement can be forgiven.

However for folk whose job it is to communicate political affairs to the wider public to default to “well, it’s complex” is either patronising or worse, ignorant. The Additional Member System is as PR goes actually very simple. Fobbing it off as complex does a – small, I grant you – disservice to the public, suggesting they are too dim to understand and it isn’t worth trying. Or that the journalist in question hasn’t bothered to try and understand it either. Either way, it’s not great.

Here’s how AMS works (post count steps)

  • Look at the constituency vote in each constituency in the region. Most votes wins the single seat in each.
  • Divide each party’s list vote by one more than the number of constituency seats they won in that region. Highest number after dividing gets the first list seat. (Or more mathematically rendered; Vote Value = Total Regional Vote/(Constituency Seats + List Seats so far + 1)
  • Repeat the same calculation, adding list seats won to the party’s total including constituency seats, until all 7 list seats are allocated.

Anyone with a pen, paper, calculator and access to Wikipedia can work out the complete AMS results by hand in a matter of minutes. It’s really not hard. I know people can freak out when any kind of maths is involved, but this is primary school level stuff – albeit with much bigger numbers than you’d have used then. Now I’m not expecting Jane Voter or Joe Ballot to go off and do these calculations, or even to know the above formula off the top of their head – I do expect journalists to do so, and not to talk down to your average punter with this “complex calculations” guff. It is possible to simply say “a system of PR lists ensures a roughly proportional result in each region” without throwing in a “complex”.

It’s not like you even have to look far to find genuinely complex electoral systems. We use the Single Transferable Vote for council elections. That is a properly perplexing system. It’s “we count these by machine in Scotland” hard. It’s “we don’t count them by machine so it takes a month to finalise the results for the Australian Senate” hard. Even if you’re a nerd like me and know the rules, given the same tools I listed above for AMS, you can’t work out the results. You need to delve down into data that exhaustively lists every ballot cast and the order of preferences on them. Even with all those votes counted and collated into a document already, it’d still take at least half an hour to do just one of the 350-odd wards in Scotland from it.

So for comparison, here are the workings of STV (again, these are only the steps after the votes have had a first count);

  • 1. Work out the quota of votes required to be elected – one more vote than the total number of valid votes divided by one more than the number of seats available. (Quota = (Total Number of Valid Votes/Seats Available +1) +1)
  • 2. Determine if any candidate has reached quota. If yes and quota exceeded, go to step 3. If no, go to step 4. If yes and quota is not exceeded, go to step 4.
  • 3. Redistribute surplus votes above quota from elected candidates. All votes move to next listed preference at a value of number of surplus votes divided by total votes with that candidate. (Surplus = Total Votes – Quota, Vote Value = Surplus/Total Votes). Return to step 2.
  • 4. If the number of candidates remaining is equal to number of seats remaining, go to step 5. Otherwise, eliminate the candidate with the fewest votes, transferring those votes to the next valid preference at their present value.
  • 5. When the number of candidates and number of seats remaining are equal, those candidates are deemed elected even if they have not reached quota.
  • 6. Repeat steps as necessary until every seat has been filled.

Bit harder, eh? The individual steps are still pretty simple maths, but there’s a lot more of them and they aren’t carried out in the same order every iteration as it depends on the results. And things get messy when you have to work out the surplus value for a ballot that has already been through the surplus wringer before.

So look, voting systems can be difficult, and it’s fine to say that. But it’s just silly to dismiss everything that isn’t FPTP as complex. We’ve had a Scottish Parliament for 18 years now, and it isn’t going anywhere. So let’s get in the habit of talking about how we elect it in a more sensible way.

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