Swingometer

[ciphergoth]

Paul's two dimensional three-way swingometer

This is still a draft version of the swingometer, posted here to get some feedback on how to make it more comprehensible and more useful. A three-way election is a rather challenging thing to illustrate on a diagram, so I hope you'll forgive this being a little harder to follow than a normal two-way swingometer!

• Point the mouse at the "2005" on the image and you'll see the result for 2005; the share of the vote for each party, and the number of seats they hold. Strictly speaking it's a projection of 2005's result onto the 2010 constituencies.
• Move the mouse around the diagram and you'll see projections for what sort of parliament you might see as the vote share changes. These projections are based on the very simple "Uniform National Swing" model, which has many failings but AFAICT more sophisticated models don't do much better in practice.
• The colour of each hexagon illustrates who has the most seats; a majority is shown in a darker colour. Larger majorities get darker colours. Where two parties are exactly equal, we use an in-between colour. Just compare the colour of the hexagons with the share of seats indicated for each one to understand the colour scheme.
• The straight lines across the diagram indicate the lead in points of the party with the largest vote share. Where the three lines meet is the point where all three parties get the same number of votes.
• A fixed proportion of votes are shared between the three main parties It would be better if you could change how many votes go to other parties, but it's much harder to do.

I have plans for updating this diagram during election night, but they're even more complicated, so I'll come to that later. Please let me know what you think - does it make sense?

Comments

[drdoug.livejournal.com]

Cool! As I tweeted, I grokked it pretty quickly when I first saw it. But that's probably not a good guide to general comprehensibility. :-)

I don't think you need the horizontal lines (marking round fifties of majorities SFAICT), just the single 'finish line' of a majority of seats. They're only remotely useful in the far outer reaches of the graph - where we are talking about majorities over 100 - and this election is so not going there. A single line would also be clearer as a finish/win line.

More labels would probably help the uninitiated, but obviously, many more and it'll get unusably crowded. Maybe try % signs after the vote shares in the popup? Would make that instantly clear what that means, I think - vote shares are the main thing that are percentages in elections, apart from swings.

The vote-share black lines could be labelled near the edges (since they're least useful), and you could leave the centre line unmarked. Then label the segments of lines something like 'L 10% > LD', 'C 20% > L', or 'L vs C +10%'. The minimal solution is just labelling them '10%', '20%', which'd be neater. But I like the idea of labelling the ends of the lines separately to cue people in to what they mean. I doubt that most people would instantly understand that - for example - the black line in the bottom left-hand corner showed where Labour had 30% greater vote share than the Lib Dems in the upper segment but where it had a 30% greater vote share than the Tories in the bottom segment. And understanding that is key to understanding the whole chart, I think.

I wonder if you could lose the +/- majority bit from the top of the seat graph columns. The +/- strongly makes one think of a change from the last election (or at least it does me), so this is another confusion you could lose. It is handy information, though - perhaps you could add it in as a line of text underneath? Saying, e.g. 'Lab maj 25' or 'Hung, Lab 65 short, Con 63 short'. (Using the same algorithm for when you show both Lab and Con short of a majority rather than just one - which empirically seems to do the job beautifully but I couldn't instantly see how it worked.) Might take up a lot of space, though.

The 2005 point is cool, and to me made it clear that the boundary changes would have seriously eaten in to Labour's majority last time. But that's because I know that the Labour majority was way more than the 21. Can you add a specific point in that popup? Or add to a series of notes at the bottom of the page something like 'The 2005 general election vote share is shown on the graph for information. In 2005, Labour won a majority of 66, but this model suggests that with the boundary changes since then they would only have had a majority of 21 seats.'

The two purple hexes look more significant than they are (SFAICT they are where the vote share whole-number percentages happen to map on to a perfect Lab/Con tie in seats) - maybe change to a vertical red/blue split?

Another suggestion for an explanatory note: You can see that the red area of the graph (Labour majority) is much larger than the blue area (Conservative majority), and both are hugely larger than the yellow area (Lib Dem majority). This dramatically illustrates the difference between our current electoral system and a pure proportional representation system (where the areas would be equal).

I don't think you want a 'change from last election' in there (crowded enough). Maybe yet another note - perhaps just adding seat numbers to 2005 note. Ah - perhaps you could have it as an extra thing underneath the whole graph. Actually, it'd be good if as well as the popup you could have a panel underneath that would show more/fuller/more fully labelled information, updated by where you last mousedover. (Mouseovered?) Ooh - actually, it could fix underneath if you clicked on a hex. That'd be very cool because as a user you'd be able to click on a point of interest, then navigate away from the page to sth else (e.g. Twitter, other poll results, or the live feed, or your blog, or whatever) and the data from the point of interesting in the graph would still be there for comparison without you having to hunt down that specific pt again. But can imagine the JS being hairy.

Out of time & chars!

[ciphergoth.livejournal.com]

This is incredibly helpful!

Will eliminate all but one of the horizonal lines as you suggest.

Have added "10%" markers on lines, but could add party names; will try it. Also will add % marker to vote share donut.

Will lose +/- in favour of text description as you suggest. Algorithm no more than cutoff at -100.

Didn't realise impact of boundary changes was so great! Yes, will add to text.

Vertical red/blue split quite awkward to achieve but very desirable - will think about that one.

Will definitely comment on how unfairness of electoral system is illustrated in text.

Really like the "click" idea. All ideas on what should be presented in the oodles of space that would allow very welcome.

Many, many thanks!

[drdoug.livejournal.com]

Algorithm no more than cutoff at -100.

Yay for absurdly simple algorithms that do a job well!

Will definitely comment on how unfairness of electoral system is illustrated in text.

My suggestion isn't quite accurate anyway, I realise.

the "click" idea. All ideas on what should be presented in the oodles of space that would allow very welcome.

For hung parliaments, it would be cool to show what majorities were possible - specifically, whether or not Lab/LibDem and/or Con/LibDem alliances would command a majority. Prob not much point to show a Lab/Con alliance commanding a majority, since it almost always would - maybe invert that one in the shiny yellow sliver and show 'Lab/Con alliance no majority' for the unlikely scenarios where this applies, to keep LibDem dreamers happy.

Many, many thanks!

You're welcome. Many, many thanks for making this! It's a cool tool and I shall use it repeatedly between now and May 8th.

[drdoug.livejournal.com]

... another quick thought on hung parliaments: in many scenarios where a party is close to a majority, the minor parties become hugely important. A Labour/SNP/Plaid/SDLP coalition is not entirely impossible, for instance, and nor is a Con/UUP/DUP(!) one. So if you're enumerating possible majority Government alliances, it'll be painfully obvious that restricting to the three biggest parties isn't covering all possibilities.

But OTOH, when you get down to that level of a handful of seats, you're well beyond the likely accuracy of a model like this, I reckon. Especially given that your model has to assume a fixed number of seats to 'others'. And there's all sorts of obscure fencepost type issues that generally don't matter but might suddenly do so in close-to-majority situation, like how many non-voting seats Sinn Fein occupy, the Speaker+Deputies, seats vacant due to death of candidates (there's at least one), etc. And of course the entirely non-zero probability that actual Independent MPs are highly significant.

So maybe just another point for the Notes.

[ciphergoth.livejournal.com]

Yes, I think trying to track the non-Big-3 parties is going to be out of reach; best that can be done is to say how many seats are held by "Other" parties, how far each Big 3 is from majority, and how far Lib-Con and Lib-Lab are.

One annoyance: if you've got 5 out of 9 seats, you have a "majority of one", but if you have 5 out of 10, you're "one short of a majority" - like BC/AD, there's no zero.

[ciphergoth.livejournal.com]

You're welcome. Many, many thanks for making this! It's a cool tool and I shall use it repeatedly between now and May 8th.

thanks! Will soon discuss plans for how to use it during election night - broadly, diagram will show makeup of Parliament assuming that *remaining* seats show a particular swing.