Thread by @bettercount_us

@UtilaTheEcon @Fix12thAmend I use four lenses to look at this problem:
① Statistical. You have a multi-dimensional distribution of voters in ideology-space, and the job of a voting system is to faithfully reproduce the median in all contested, policy-relevant dimensions. This is PoV of the original thread.

@UtilaTheEcon @Fix12thAmend ② Deliberative. Goal is to elect a parliament that can creatively find solutions to common problems. Viewpoint diversity is usually a plus, except that some people, just frankly toxic and closed-minded, should be kept out.

@UtilaTheEcon @Fix12thAmend ③ Parliamentary/coalitional. Goal is to "form a government", with a policy platform that has (indirect) buy-in from a majority of voters. Rich poli sci literature about pre-election vs. post-election coalition formation; my read is it's best to have a bit of each.

@UtilaTheEcon @Fix12thAmend ④ Hegelian. You want an ideological landscape that's dynamic over time, that responds to changes in reality with new solutions. In order for that to work, you need to have room for more than two parties (ie, room for "synthesis" to arise in addition to "thesis" & "antithesis").

@UtilaTheEcon @Fix12thAmend In schema ④, Hegelian, note that 3 really is the most dynamic number of major parties. 1 or 2 gets stuck in inertia, while with too many splintered parties, none of them has the clarity/focus/vision to develop a coherent platform. Petty squabbling, gets nowhere.

@UtilaTheEcon @Fix12thAmend The lesson I take from all 4 lenses? You want a balance between broadly representing everyone, and distilling down to fewer, stronger parties. Let me rephrase that idea from each perspective:

@UtilaTheEcon @Fix12thAmend ① From a statistical perspective, if your job is to maintain the median in multidimensional space, then it's important to minimize wasted votes, but OK to represent extreme tail voters by the nearest point on the border central 50% blob. Think box plot, 25-75 percentile.

@UtilaTheEcon @Fix12thAmend Note that, even from a statistical perspective, not a good idea to collapse everything to a single point, to have a legislature where everyone is at the exact middle. Because ideology is multidimensional, "exact middle" is hard to define; best to cover 25th-75th percentile.

@UtilaTheEcon @Fix12thAmend ② From a deliberative perspective, you want viewpoint diversity, but don't want people who are toxic, arrogant, closed-minded. So, best to set incentives to favor those who can compromise. Goal is to maintain good cognitive diversity, but it's OK to rule out the extreme fringe.

@UtilaTheEcon @Fix12thAmend ③ From a parliamentary/coalitional PoV, you want some of the work of negotiating compromise to happen intra-party, before the election; "big tent" dynamics. & some inter-party, after the election; governing coalition. If all happens in one of those, the other is a waste of time.

@UtilaTheEcon @Fix12thAmend ④ From a Hegelian PoV, you want effective number of parties (ENP) to be in the range of 2.5-3; enough room for two strong alternatives, plus a nascent third synthesis option. Since it should be dynamic, in practice this won't be exactly 3 equal-sized parties, ...

@UtilaTheEcon @Fix12thAmend ...but rather, 1-2 parties each at 3 main sizes large (40%ish), medium (20%ish), and small (<10%). 4-5 parties total, but "effectively" 3. (There's actually a formula for "effective number of parties" which captures this.)

@UtilaTheEcon @Fix12thAmend So. From all 4 of my lenses, the lesson is, you want a Goldilocks number of parties; 4-5 of them total, with 1-2 of those larger than the rest. Not too many, not too few.

And that's something you can design a PR method to do. Specifically, PLACE voting: electowiki.org/wiki/PLACE_FAQ

@UtilaTheEcon @Fix12thAmend I know; I sound like a looping video clip (haven't heard an actual "broken record" in decades) on this. But that's because there's a lot of thought behind PLACE, theory that wasn't really available over a century ago when people were designing STV or MMP or (gag) closed list PR.

@UtilaTheEcon @Fix12thAmend PLACE is, very consciously, designed to aim at the "Goldilocks" point: an eventual equilibrium with not too many parties, not too few. It's also designed to be non-disruptive, so it approaches that equilibrium gently; in USA, the 2 existing parties would still dominate for now.

@UtilaTheEcon @Fix12thAmend That conscious, intentional method design means it won't be everyone's favorite method proposal. Some reform activists hate all parties — that's not PLACE. Some folks like the US 2-party status quo — not PLACE either. But in my opinion, that intentionality is PLACE's strength.

@UtilaTheEcon @Fix12thAmend /end thread. @threadreaderapp, can you do your thing?

@UtilaTheEcon @Fix12thAmend @threadreaderapp Whoops, I guess that with @threadreaderapp you need to say "unroll". So: unroll, please.