Sunday, 27 February 2011

Incompetent campaigning

Two weeks ago, I noted that, apparently lacking good arguments in favour of FPTP, the No2AV campaign were instead campaigning on cost - and had significantly exaggerated the cost through a mix of accounting fraud and the political technique commonly known as "making stuff up".

Fortunately for No2AV, the Yes campaign seems determined not to capitalise on this mistake.

It should be a major mistake - if you start complaining about the cost of democracy, what other "cost saving" measures are you willing to entertain? Less frequent elections? Increased restrictions on suffrage? Dictatorship? We don't have democracy because it's cheap but because it's worth it.

Rather than pointing this out - and indeed, pointing out that even the massively inflated £250 million price tag is insignificant - the Yes To Fairer Votes campaign have instead chosen to ... complain to the Advertising Standards Authority

The ASA replied to point out that they don't regulate political campaigning, to which the Yes campaign's response was to start a petition asking them to start doing so.

Yes. Really.

Reasons this is a major mistake include:

  1. The ASA doesn't regulate political campaigning, and it would probably need legislation to give it that power. Chances of this happening before 5 May: nil
  2. The ASA takes months to make decisions over commercial advertising. Chances, even if it decided to unilaterally take power over political campaigning tomorrow, of it returning a verdict before 5 May: nil
  3. The ASA's typical verdict, in the cases where an advert is found to be misleading, is an instruction not to run an advert making that claim again. This is virtually useless, of course, since everyone has already seen it. Indeed, there are a few companies who specialise in exploiting this commercially. Chances of an ASA ruling, even it had the powers and speed to make it before 5 May, making any difference: nil

They should be taking this major opportunity to portray the No campaign as self-admittedly anti-democratic. They should be pointing out that we can afford a better democracy. Instead, they're chasing after a giant red herring.

Just in case it makes it clearer, here's a quick picture.

Edit: As MarkWadsworth points out, GDP is around £1,400 billion, not £2,250 billion. I've updated the graphic, and corrected the figures in the rest of the post.

Graphical representation of AV cost

Description: Most of the image is filled with a large blue rectangle, labelled "Annual UK GDP: £1,400,000 million.
Inside that is a smaller yellow rectangle to scale with the rectangle labelled "Annual government spending: £644,000 million"
Inside the yellow rectangle, barely visible, is a tiny purple rectangle (again, to scale). An arrow points to it indicating that this is the £250 million alleged cost of AV.
Below the diagram, the text: "Real cost of AV: £20 million (too small to show)", and then in larger type "Good democracy is worth paying for. We can afford it: Vote YES to AV."

£20 million is probably an overestimate too, but should comfortably cover the slightly larger ballot papers needed, any voter education campaign, user research into the best format of ballot paper, and other one-off transitional costs.

If we can't spend - once, not every year - around a fifth of a percent of a percent of our national GDP on improving the voting system (or even a fiftieth of a percent, if you accept the massively inflated figure), then we are basically concluding that democracy is too expensive in general1.

This sort of campaign - and the Yes campaign can afford better graphics than I can put together in a few minutes - could completely nullify the No campaign and leave them without much of an argument.

It should be an extremely easy argument to win, but the Yes campaign seems determined to lose it anyway - I agree with Matt Wootton's assessment that the Yes campaign simply does not understand how to run a political campaign. (Their letter-writing to the BBC over the use or otherwise of 'reform' is much the same)

So, that delicious red herring?

There is, absolutely, a strong argument that political campaigning should be regulated to make sure that candidates/supporters can't intentionally deceive the electorate.

In practice, though, there's no reasonable way to do this for a referendum. There is no candidate, and there is no extent to which a supporter could falsely campaign that would make it proportionate to disqualify a referendum option. Fines or disqualification from further campaigning on the issue are not major deterrents in the context of a one-off referendum campaign. (Whereas in elections, which are regulated somewhat, losing the seat that you won can be a deterrent)

Additionally, there's the timescale. The determination of the election court over former MP Phil Woolas's campaigning took months to conclude that he had intentionally misled the electorate about his opponent's character. Likewise, any robust system for determining whether the electorate were deceived (or whether the disputed point was just fair differences in opinion), and whether this was intentional, would take months with respect to a referendum. The capacity to respond within a couple of days would be virtually impossible (indeed, submitting vexatious requests would be a good way to slow the system and your opponents even if it could respond this quickly)

The ASA certainly isn't the right body to be doing this, but there aren't any other suitable ones either.


1If you genuinely prefer FPTP to AV, of course, then any money spent on switching to what, for you, is an inferior voting system is obviously mis-spent. But it would also be a bad idea for you to switch to AV even if it turned out to save a little money. Either way, the financial argument isn't compelling.

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Saturday, 26 February 2011

The danger of headline statistics

One of the most common ways of misleading people with statistics is to carefully select a statistic from a larger data set, and then make inferences from that statistic as if it were representative of the data set. This can lead to headline statistics which imply the opposite of the underlying reality.

Being able to spot these and show up the misdirection is sometimes quite tricky.

For a (relatively straightforward) example, a statistic that often gets quoted in arguments about gender equality is that "over 80% of those dying in workplace accidents are men". I'll use this to illustrate some of the common problems with these sorts of headline statistics.

[trigger warning: workplace deaths, murders]

Problem 1: scoping of the statistic

There's no indication on this statistic of what country it's related to or when the data was gathered. I couldn't find a formal breakdown for the UK at all, and didn't feel like guessing from the names on the accident summaries. Looking at the available statistics for other rich industrialised English-speaking nations, the headline figure is almost certainly true, though.

However, not having a year or country specified makes it very difficult to look beyond the headline at the details - which details?

Specifying "workplace accidents" also statistically excludes those cases where someone is intentionally harmed while working, since that would be compartmentalised as a police rather than a health and safety matter. The various murders of sex workers would not, for instance, be counted, which significantly skews the gender balance of the statistics, but not of the actual workplace dangers.

Problem 2: implying a cause

The implied cause is that there is discrimination against men which causes them to die more in workplace accidents. There are actually several other factors involved.

Who can die in the workplace?

Firstly, more men than women have jobs at all. Here's the UK's Labour Force Survey.

In 1971, the ratio of men to women in employment was 3:2. 1

In 1992 - the first year for which detailed statistics are available - the ratio is closer to 5:4, but the detailed statistics show that almost all the men are in full-time employment, while only slightly over half of women are.

In 2010, the base ratio is around 8:7, but the full-time/part-time patterns are much the same. There has been a slight rise in the number of men working part-time, and a slight rise in the number of women working full-time, since 1992, but it's not a major difference.

If we assume on average that a part-time worker works half the hours of a full-time worker, that means that men are collectively working in paid employment between a third more and twice as many hours as women collectively work in paid employment (depending on the year)

So, some of the difference is caused by the difference in hours worked. Men are more likely to die at work because they collectively spend longer there. Note that greater male employment is generally not considered evidence of discrimination against men.

Who is likely to die at work?

Some jobs are considerably more dangerous than others. The Health and Safety Executive collects data on fatal injuries at work (including fatal injuries to members of the public who were in a workplace).

Many of the deaths of workers occurred in the Construction and Agriculture sectors, both of which mostly employ men and involve large amounts of heavy machinery.

There are a number of reasons for most employees in these sectors being men, but they are not reasonable to describe as discrimination against men.

Problem 3: missing the real problem

The problem with workplace deaths is not that men die in workplace accidents, it's that people die in workplace accidents. The correct thing to ask the magical society fairy for is an end to workplace accidents, not an equalisation of who dies in them by gender.

There can't be many accidents that wouldn't have happened if - all else equal - the worker in the unfortunate position hadn't been a man2. Nor are there likely to be many potential fatal accidents which were only avoided (or at least not fatal) because the worker wasn't a man.

So, primarily, the solution is to try to make workplaces safer. This - at least in the UK - is happening. Fatal workplace accidents have fallen to less than a half of their rate in the early 90s3. A combination of regulation and guidance of health and safety has helped make the UK one of the safest places in the world to work4 (though that's not the only reason, of course; see below).

Problem 4: not distinguishing between primary and secondary effects

There are privilege-related issues here - class, gender, immigration status, and disability, for instance, can all lead to situations where someone has to take a job which is less safe. Internationally, the UK is able to use its trading wealth to export a lot of the more dangerous work to other countries so that foreigners die on our behalf.

These are all important issues, with established campaigning groups for all of them, especially in the trade union movement.

For immigration status, it's a direct consequence of the harsh treatment we give to undocumented migrants - and the low value we place on their lives as a society - which makes it easy for unscrupulous employers to exploit them knowing that they can't easily report their employer to the authorities.

The danger they are in is a primary consequence of their immigration status, and so the solutions have to consider that: generally making workplaces safer won't help because there is no practical mechanism for enforcement against that employer (who is already breaking a vast range of laws and won't mind breaking health and safety law too).

For gender, the disparity in workplace accidents (not workplace deaths in general - see above - but accidents specifically) is not a primary consequence of the workers' gender, but a secondary effect from a number of gender-related issues:

  • Men are more likely to have paid work, and for more hours, due to well-documented discrimination against women, childcare being seen as primarily (or even only) a woman's job, and so on.
  • Men (especially working-class men) are encouraged into paid work requiring physical activity, whereas women are discouraged from this. This happens both at the stage of career choices, and in the workplace itself where hostile anti-women environments can be self-perpetuating. The "men's work" is generally better paid than the "women's work" for equivalent knowledge and experience.

As a consequence of these, there are more men in dangerous jobs than there are women - but it's a consequence of discrimination against women, not discrimination against men: all of the components that cause it are positive for men, even if this one side-effect is negative.


The headline statistic is often used to imply discrimination against men. The underlying data shows no such thing (though there are genuine issues related to gender and other aspects of discrimination).


1 As with all UK official statistics, the existence of people who are neither men nor women is ignored. Depending on the method by which statistics are collected, misgendering of at least some of the trans people in the sample is also extremely likely. The lack of useful data means that I can only discuss men and women for this post.

2 I've no idea about how you'd ethically go about testing this, but it's not a completely outlandish hypothesis that since men are socialised to be more confident than women, and get more tolerance for minor errors, they're more likely to cut corners on safety procedures as confidence shades into recklessness, and this accounts for a higher proportion of accidents in male-dominated workplaces.

3 Adjusted for the relative proportions of industries, the UK has the lowest fatal accident rate of all EU countries, and less than a third (per 100,000 workers) of the rate in the USA.

4 Naturally, rather than taking some pride in this achievement, many of the popular papers and politicians feel that we aren't, as a nation, killing enough workers, and want to see much of the protective regulations repealed. The people suggesting this generally do not work in jobs involving heavy machinery, steep drops, or other dangerous environments, where the trades unions representing the actual workers tend to be quite in favour of workplace safety.

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Friday, 25 February 2011

Friday Links

Monday, 21 February 2011

Arguments for Alternative Vote

Having covered the arguments against Alternative Vote, I should probably also cover its advantages. Again, because it's topical, I'll also compare Alternative Vote (AV) directly against the First Past The Post (FPTP) system, and list other voting systems that share these advantages.

There are no ideal voting systems - every voting system is good for some things and bad for others. When choosing a voting system, you need to consider the factors that are important to you, and pick a system that exemplifies those factors, while only being bad at things that don't matter so much to you.

There are also some common false arguments for Alternative Vote

AV balances core support and broad appeal

The candidate elected under AV requires sufficient broad appeal to gain transferred votes from eliminated opponents, but also sufficient core support to avoid being eliminated in an early round.

Voting systems which only require broad appeal have a tendency to massively benefit 'centrist' candidates even if they are no-one's first choice, which can harm the standard of political debate. Conversely, voting systems which only require core support can be extremely divisive and exacerbate tensions between communities.

Candidates with strong core support and very little broad appeal will find it very difficult to win AV elections. An "anyone but X" trend in the electorate is therefore magnified in AV, making it easier to remove unpopular politicians and parties from office.

Depending on your point of view, this may not be a good thing, which is why there's a very similar entry in the "arguments against" list.

Other voting systems

Borda or Range Voting, and to a lesser extent Approval Voting, also share this property, although the increased possibilities for tactical voting in those systems may make AV stronger in this regard.

Proportional Representation systems such as Single Transferable Vote balance support levels in a different way. Nevertheless, Single Transferable Vote (unlike the List systems) does provide some bonus to candidates who can appeal to a broad electorate while also electing candidates in rough proportion to their core support.

If extreme tension between disparate communities is a problem, using Proportional Representation where possible is strongly recommended. Single-seat systems such as AV are not sufficient for this problem (they may be suitable for electing a single President, but not for a Parliament).

Compared with FPTP

FPTP formally elects candidates based solely on their core support. There may be some element of broad appeal considered due to tactical voting from the voters in the core support of third-party candidates, but this is considerably weaker than in AV.

This is essentially the major point of using Alternative Vote, so it's unsurprising that it does better than other voting systems. If balancing core and broad support is your aim (and a proportional representation is either unwanted, not an option, or inappropriate for other reasons) then AV is ideal.

AV allows independent candidates

AV, like most voting systems, does not excessively penalise independent candidates. Party affiliations are not required to stand, and a lack of party affiliation only harms a candidate in terms of the campaigning resources and volunteers they have access to, not in terms of a penalty built in to the electoral system.

Other voting systems

List systems of proportional representation heavily penalise independent candidates as a consequence of the way the votes are counted. Most other voting systems treat independent candidates and party candidates identically.

AV does have a particular advantage beyond most other voting systems in that a successful independent candidate may find it easier to beat an incumbent, or maintain their position, provided their core support is strong enough, by getting transfers from sympathetic supporters of party candidates.

Compared with FPTP

AV, by allowing the collection of transfer votes, is generally better for independent candidates who amass a strong core vote - thousands instead of the tens or hundreds most independents get - and are well-placed to pick up transfers from the party candidates they get ahead of.

Such independents are very rare, under any electoral system, but have an even harder task under FPTP than under AV. The same applies to mainstream minor party candidates (e.g. UKIP or Greens)

AV is easy to count

AV is one of the most straightforward systems to count. Each vote is only being counted in a single position at a time, and only when votes are transferred do the preferences need to be re-examined.

This straightforwardness makes it possible to count AV by hand, and to use it for elections at meetings even without pre-prepared ballot papers.

Other voting systems like this

First Past The Post, List systems and Approval Voting are also straightforward to count. Pairwise voting is straightforward to count in the context of shows of hands at a meeting, but is less straightforward when using ballot papers for a secret ballot.

Single Transferable Vote is no harder to count than AV in terms of the mechanics of counting, but depending on the variant of STV in use, may require complicated calculations.

Other voting systems tend to require repeated examination of ballot papers, and so are difficult to count by hand.

Compared with FPTP

AV is marginally slower to count than FPTP, but not significantly more difficult. For an election with 4-5 credible candidates, in the worst case, an AV election will probably take around twice as long to count as an FPTP election.

Numerous non-credible candidates with very low vote totals add significantly to the number of rounds in the AV count, but provided the vote bundles were left sorted after the first counting round, this will not significantly increase the count time.

AV discourages tactical voting

AV strongly discourages tactical voting. While there are theoretical situations in which tactical voting is possible and practical, it is extremely difficult in general to identify these situations in advance.

The rare situations in which it is possible are covered in the 'arguments against' list.

Other voting systems

Condorcet is the only other single-seat system that discourages tactical voting, and it does this considerably more effectively than AV.

Proportional Representation systems such as Single Transferable Vote or List systems also largely avoid tactical voting.

Compared with FPTP

FPTP strongly encourages voters for third party candidates to vote tactically for one of the two major candidates in a constituency instead, and also gives an incentive to the two major candidates to actively encourage tactical voting.

Conversely, AV makes tactical voting generally impractical, and the forms that exist are not generally ones that political parties would encourage.

False arguments for AV

There are some arguments for AV which are either entirely untrue, or depend on the context in which AV is being used.

AV ensures that a candidate has the support of the majority of voters

Not really. This is usually implied from the fact that a candidate needs 50% (plus one) of the votes remaining at the current stage of the count to be elected.

This is not usually the same as the number of votes cast, unless the rules require every voter to use all their preferences. In optional preference AV (the form proposed for the UK), voters can use as many or as few preferences as they like. This means that in the late stages of the count, a vote without a complete set of preferences might not have any remaining candidates to be transferred to, because the voter couldn't decide between what were to them all unsatisfactory options.

If this happens, the vote plays no further part in the count, and the target number of votes (also called the quota) is reduced slightly to compensate.

In England, between 60% and 90% of constituencies - depending on how the election went - would probably have the winner receiving at least 50% of the original votes in the final round. The vast majority of the remainder would be in the 48%-50% range, with below 45% being exceptionally rare. (I don't have sufficiently reliable polling data for UK countries other than England to make a guess at those, but having four or more major parties rather than just three would generally make wins below 50% of the original votes a little more likely)

[Edit 11 April 2011: The Swingometer now gives basic statistics on the proportion of seats where fewer than 50% of the original votes are held by the winner, and the "worst-case" percentage needed for that scenario.]

However, a couple of percentage points here or there is not the main reason this argument is false. The major reason is that it relies on the interpretation "giving someone a preference - any preference - means support".

This is not necessarily true, of course. In a six candidate election, an unlucky voter who sees their four favourite candidates knocked out may still have an opinion over which of the other two is least bad, but to call their choice 'support' for their fifth may be excessive.

Another possible definition of "support" is "preferred to the alternatives", but while the elected candidate is guaranteed to be preferred by the electorate to any remaining candidates, it is possible that there is another candidate, eliminated at an earlier round, whom a majority of the electorate would rather have seen win.

A small election to demonstrate
Number of ballot papersFirst preferenceSecond preferenceThird preference
10 votersAliceCathBob
9 votersBobCathAlice
2 votersCathAliceBob

In this election, no candidate has half the votes, so Cath, with the fewest votes, is eliminated from the election, and her two votes redistributed to the remaining candidates. They both go to Alice, so Alice wins. But 11 of the 21 voters - more than half - would in a straight choice between Alice and Cath have picked Cath.

If you want a voting system where the winner is guaranteed to have majority support over any other candidate (should such a winner exist, anyway - it's not guaranteed), then the Condorcet system should be used, rather than AV.

On the other hand, if you want - as above - to balance both core support and broad appeal, this property of AV is an advantage. Should Cath really be elected in the election above when hardly anyone places her as a first preference? (The answer is "maybe": it depends on what you consider important for an election system)

AV generally requires the support of a larger proportion of the electorate than FPTP. But it doesn't always require majority support. (Proportional Representation advocates, at this point, would point out that requiring majority support is not a universal good thing anyway - allowing a party with 10% support to get 10% of the seats is the whole point of PR systems such as List or Single Transferable Vote)

AV prevents "safe seats" compared with FPTP

It's really quite hard to assess how much impact AV has on this. Any AV election result could, after all, also be achieved under FPTP in theory given sufficient tactical voting (or candidates withdrawing - former MP Martin Bell's win in Tatton, for instance). In the UK, the third of MPs who currently get half the FPTP votes already are extremely likely to keep their seats under AV.

While the power of AV to avoid splitting an "anyone but X" vote is extremely strong and important, the majority of safe seats in the UK are safe because the incumbent has massive levels of local support, not because the opposition is split.

Both Labour and Conservative supporters have worried that the supporters of the other party would join forces with Lib Dem supporters under AV to lock them out of government. In practice, this is very unlikely to actually happen, except where an "anyone but X" sentiment is widespread across the country (and in that case, that party is probably doomed under FPTP as well).

AV will make some seats less safe - semi-marginal seats are likely to become fully marginal, and semi-safe seats might become semi-marginal and vulnerable to an exceptional election campaign or extreme unpopularity of the incumbent, but the effect will be fairly subtle. Conversely, depending on how votes tend to transfer between parties, some currently marginal seats may become relatively safe.

There is also the possibility in the long term of the lack of need to vote tactically under AV opening some very safe seats up to a challenge from minor parties on the same 'side' of the political spectrum as the incumbent (for instance UKIP in a safe Conservative seat), but this is likely to take several elections to become apparent.

So, while AV will reduce the safety of some seats compared with FPTP, the effect is not likely to be spectacular.

To largely avoid safe seats, a proportional representation system is needed - either Single Transferable Vote, or an open List system. Even then, successful parties can usually get a few seats which are safe against all but the worst national landslide victories.

[Edit, 14 April: More detail in the new post Alternative vote and safe seats. The swingometer has also been updated so you can look at scenarios yourself.

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Saturday, 19 February 2011

Arguments against Alternative Vote

Since people keep finding my earlier post on AV and proportionality when searching for "arguments against alternative vote", I thought it was probably time to actually set out the list of those arguments. (Arguments in favour of AV get a separate page, though in some cases whether an argument is positive or negative depends on what you're looking for in a voting system)

You should probably skip the rest of this post if the merits of various electoral systems don't interest you.

For each point, I'll describe a problem with Alternative Vote (AV) (which might not necessarily be a problem for you personally), and say which other voting systems can be used to avoid this problem.

Since a lot of the recent interest is probably to do with the upcoming referendum, I'll also explicitly say how the other referendum option, First Past The Post (FPTP), does on the same problem.

All voting systems are inevitably flawed in some way - there is no one perfect correct way to count votes. So picking a voting system is about considering the problems of the possible voting systems, and ignoring those that you don't think are problems.

I also list a few things that are not arguments against AV, but are sometimes presented as such.

AV is not proportional

Because Alternative Vote is only suitable for electing a single candidate, to elect multiple candidates to a body, to use AV you need to divide the electorate up into multiple constituencies, each electing only a single candidate.

This operation means that generally the strongest one or two parties get by far the highest number of seats, with other parties getting far fewer or even none. The distribution of the voters within the constituencies can also make a large difference, with parties with geographically-concentrated support doing better than parties with geographically-separated support.

Two parties could get identical numbers of first preference votes (and indeed second and further preference votes) across the electorate as a whole, but could get vastly different numbers of seats.

In the UK this effect significantly benefits Labour and the Conservatives (by a similar amount), and harms every other party.

To avoid this, use...

The only sensible voting systems that can avoid this problem are ones using constituencies returning multiple candidates. Either Single Transferable Vote or one of the List Voting systems will give a result where the number of candidates a party gets is roughly proportional to the number of voters for that party.

What about FPTP?

I cover this in far more detail in the earlier post. In summary, neither AV or FPTP are proportional systems. Which gives the result closer to proportionality will depend on fine details of party affiliation, geographical distributions, constituency boundaries, and so on - and will probably vary from election to election anyway.

There is no reason to pick AV over FPTP, or FPTP over AV, on the grounds of proportionality - if you don't want proportionality, pick either. If you do want proportionality, pick a different system if you can, or find another way to decide if you can't.

Let's call this one a draw.

AV is not monotonic

Monotonicity is an obscure property of voting systems, but it's generally considered quite important. It states that, if candidate A is currently winning the election, and a number of voters change their votes to be more favourable to candidate A, this should not cause candidate A to lose the election.

Or, more simply: getting more votes shouldn't make one's situation worse. "Monotonicity" is also called "Non-perversity", for obvious reasons.

AV, unfortunately, is not monotonic. Consider the following small election with three candidates - Alice, Bob and Cath - and a few voters. To make the example simple, all the voters follow one of three patterns for their ballot papers.

Here are the votes
Number of ballot papersFirst preferenceSecond preferenceThird preference
10 votersAliceCathBob
9 votersBobCathAlice
8 votersCathAliceBob

There are 27 votes, so 14 votes are needed to be elected. No-one has 14 votes yet, so Cath, who has the lowest number of votes, is eliminated from the election. The second preference of Cath's 8 votes are looked at, and they're all for Alice. The votes are added to Alice's total, and on the second round of counting she is ahead 18 votes to 9, which is enough to win the election.

But what would have happen if Alice's campaign had been a bit more effective, and two of the Bob voters, rather than putting Alice last, had put her first, Bob second, and Cath last?

The new vote totals are
Number of ballot papersFirst preferenceSecond preferenceThird preference
10 votersAliceCathBob
2 votersAliceBobCath
7 votersBobCathAlice
8 votersCathAliceBob

Still no-one wins on first preferences alone, but rather than Cath being the last-placed candidate, Bob is. So Bob is eliminated instead, and those 7 votes get transferred to their second preference candidate - Cath.

Cath now wins by 15 votes to 12 on the next round of voting. By getting some voters to give her a first preference rather than a third, Alice has ended up losing the election!

How big a problem is this in practice?

It sounds very serious, but fortunately, in practice, this doesn't happen that much. (If it did, no-one would ever use Alternative Vote).

[Edit 7 April: For a more detailed analysis of how common non-monotonicity is, see the later post. You can also use the swingometer to find out which seats might be affected.]

In almost all cases, getting more votes will improve a candidate's chances of winning the election.

The major reason that it isn't a problem is that it's both rare and very unpredictable. Unless you have almost perfect polling, seeing when an election might give a non-monotonic result is very difficult. In the situations where your candidate ends up in a non-monotonic 'trap' and loses, it's possible to get out of the 'trap' by picking up extra votes or by losing some votes - and it's always safer to try for even more votes.

The consequence is that it's a rare election that's close enough to have this behaviour at all, and an exceptionally rare election where another candidate can actually take advantage of it. (The exception is when the vote is not a secret ballot, and later voters can incorporate earlier votes into their plans - in this case, a sufficiently quick-thinking candidate might just be able to use this)

To avoid this, use...

...just about anything else. Single Transferable Vote has the same problem - though even less predictably. Every other voting system that I know of is monotonic.

What about FPTP?

FPTP is monotonic. AV is non-monotonic in rare situations. If monotonicity is important to you, FPTP has a narrow advantage here.

AV allows tactical voting

'Tactical' voting is where a voter completes their ballot paper in a way that is not their real preference order, with the aim of getting a better result than they would have done if they were honest.

For instance, in the election above where Alice wins, Bob's voters generally do not like Alice. If some of them put Cath rather than Bob as their first preference, then Bob still won't win, but neither will Alice, and Cath is at least preferable.

It's easy in theory, but it's rarely actually done in practice, because it means deliberately throwing away a good position in the election to benefit a different candidate.

So, for instance, in a Labour/Conservative marginal in the UK, where Labour are going to be ahead on first preferences, and the transfers of votes from Lib Dems and minor parties are not predicted to close the gap completely, people who would "honestly" put the Conservative candidate first might instead put the Lib Dem candidate first, and push the Conservative candidate down into third place. Conservative transfers of second preferences are likely to be overwhemingly in favour of the Lib Dem rather than the Labour candidate, so the Lib Dem wins rather than the Labour candidate.

(This example works equally well with Labour and the Conservatives reversed, by the way).

That's the theory. In practice, though, it only works in seats which are extremely marginal to begin with. In those seats, the choice is between:

  • throwing away a good second place (or even first place if your polling is a bit off), and so letting the third-placed candidate win.
  • campaigning harder for second preferences from the third-placed candidate and winning on transfers yourself.

It's generally considered better to lose narrowly in second place - and so be a definite contender for the seat next time, with all the central party resources that implies - than get knocked back into a distant third place and have the party focus its resources elsewhere next time.

It's also really difficult to campaign for - Labour candidates going around saying "Vote Lib Dem to keep the Conservatives out" are going to get very odd looks (and probably thrown out of the party, too).

To avoid this, use...

It's very difficult to find a voting system which isn't at all susceptible to tactical voting. For single-seat constituencies, Condorcet is the best option. For multiple-seat elections, any PR system will be almost immune, but not completely.

AV isn't bad for single-seat elections, though - I think only Condorcet is more resistant.

What about FPTP?

Both FPTP and AV are susceptible to tactical voting, but FPTP has it far worse.

In AV, the tactical vote is to throw away a possible first or second place to improve the chances of a somewhat acceptable winner coming up from third. It's very difficult to do correctly, and no-one is likely to try.

In FPTP, the tactical vote is to throw away a possible fourth or fifth place (or weaken a third place), to improve the chances of the better of the top two. It's relatively common and somewhat effective.

If you want to avoid the need for tactical voting, AV is by far the better of the two.

AV is biased against extreme candidates

Is this a flaw? It is if you are extreme.

Extremist candidates are not going to get 50% of the first preference votes (if they were doing that well, it would be somewhat misleading to call their political views extreme in the context of that election). Because they're so extreme, though, it's also very rare that anyone will give them a decent preference for transfers, which means that they're very likely to go out of the election in an early round.

To avoid this, use...

Any proportional representation system, except those which require a high minimum percentage of the vote to get any seats.

What about FPTP?

FPTP and AV both have a tendency to benefit parties around the centre, but these tendencies behave in different ways.

FPTP benefits the two largest parties near the centre (in the UK, Labour and the Conservatives), and makes things very difficult for anyone else.

AV also benefits those parties, but gives a smaller benefit to parties between the two biggest (such as the Lib Dems).

Its effect on parties that are not extremist but are outside the space between the big two is hard to tell, but the evidence suggests that AV would make things a little easier (though not much) for most left and right parties such as the Greens and UKIP, but would make things much harder for extremists such as the BNP.

Which of the two systems you prefer on this basis probably depends on who you consider extremist, whether you are one yourself, and whether you think having a few extremists elected is good or bad for the government as a whole.

Selecting a preference order is complex

It's certainly true that numbering candidates in order of preference is more complicated than just picking a single favourite candidate.

Depending on the design of the ballot paper, this may also cause accessibility problems.

To avoid this, use...

Either a non-preferential system such as FPTP or a List system, or a system such as Approval Voting where voters place identical marks by all the candidates they approve of.

What about FPTP?

FPTP ballot papers are a bit easier to complete. Whether this matters to you depends on how difficult you think the electorate are likely to find "number the candidates in order of preference, starting with '1' for your most preferred candidate.", and how much impact you think voter education is likely to have on this.

In an optional-preference AV system, which is the one proposed for the UK, the problem is less severe as there's no need for voters to specify more preferences than they want to (and they can only specify one, if they want).

False arguments against AV

Edit: 2 April 2011 - since this post was written, another false argument has come up: Would elections be decided on BNP second preferences? (My conclusion: no more than they are now)

AV requires voting machines or other electronic or mechanical voting assistance"

No. AV was invented and used long before any of that technology existed. Most of the AV elections I've participated in have used normal paper ballot papers, counted by hand, without any problems at all.

"AV is complex to count"

No. An AV count will usually take longer than a FPTP count unless the result is very obvious, but in practice not by much. It will be considerably quicker than the count for most other election systems except List systems and FPTP. Also, while the count will take slightly longer, the counting process is not significantly more complex than that for FPTP.

I've participated in several AV counts, and been in charge of a few. While the voting process is a little more complex, the counting process is not.

"AV gives some people multiple votes"

No. Alternative Vote is intended as an alternative to holding multiple rounds of run-off voting, by collecting all the information needed on a single ballot paper. Rather than holding the votes on separate days, requiring multiple rounds of elections, and delaying the final result by weeks, the voters preferences are collected, and used to find out what would have happened - the ballot paper acts as a proxy for the voter.

(In US English, Alternative Voting is called Instant Runoff Voting, which makes this somewhat clearer)

A typical ballot paper might read as follows (the voter has chosen not to use all their preferences):


This means:

  1. In the first round of voting, vote for Cath.
  2. If there's a second round of voting, and Cath hasn't been eliminated, vote for Cath again. Keep voting for Cath if possible.
  3. If Cath gets eliminated, vote for Dan instead in the next round.
  4. If Cath and Dan both get eliminated, vote for Alice.
  5. If Cath, Dan and Alice all get eliminated, don't bother showing up for the next round of voting.

Rather than the voters having to go back and forth to the polls every week until someone gets 50% of the votes, the voters fill in a ballot paper that acts as their proxy in the voting. That ballot paper will then vote in every round it can until either someone gets 50% or it runs out of instructions.

Every voter gets one vote each round, if they want. (People who don't specify all their preferences won't get a vote in future rounds once their specified preferences run out - which might never happen, of course - just as people who don't show up to vote in the later rounds of a run-off election don't get a vote)

AV doesn't give some people multiple votes - it gives everyone one vote, but means that people who are happy with the way their vote is going don't need to go back and keep saying that.

AV will lead to permanent coalition government

No. It's difficult to predict the effects of a change in voting system, but the only recent UK general election in which AV would have been likely to give a coalition government and FPTP didn't anyway is the 1992 general election (and given that Major's Conservatives lost their majority by the end of that Parliament anyway, it might be more accurate to say that AV would only have given a coalition sooner in that election).

Australia, which uses AV, has had considerably fewer coalitions1 than the FPTP-using UK. Conversely Canada, which uses FPTP, has had considerably more coalition governments than either the UK or Australia.

Whether AV or FPTP leads to coalition governments depends far more on the strength of the third and fourth parties than on which of the two systems is used.

AV would make coalition governments marginally more likely in the UK, but only very marginally. Majority Conservative or Labour governments would still be the norm.


1 Edit 17 March: As Tim Roll-Pickering points out in comments, this depends on what you count as a coalition. To be more specific, short-term alliances between parties for the duration of a single Parliament, needing to be agreed only after the votes are cast and the majorities known, are not significantly more likely under AV in the UK context. Long-term alliances made possible by a change in voting system are a different matter, and beyond prediction for now.

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Friday, 18 February 2011

Friday Links

And finally, in perhaps the first and only unequivocally positive idea of the coalition government. HarpyMarx: Here comes Larry the cat....

Tuesday, 15 February 2011

The cost of democracy

The No to AV campaign, apparently lacking good arguments in favour of First Past The Post, has claimed that AV would cost too much.

Plenty of other commentators have already pointed out that their claims are absurd - including the cost of the referendum itself as a cost of AV is the sort of accountancy that would get you investigated for fraud if you tried it on your corporate expenses; paying a huge amount for unnecessary vote counting machines1 that we wouldn't actually buy; and so on.

The idea that a relatively trivial sum should be used as an excuse not to run a democratic process in one of the richest countries in the world has also been widely criticised, and rightly so. Next Left, for instance, points out that extrapolating the votes in a seat from a statistical sample would be even cheaper - Isaac Asimov's Franchise being the end of that road. (I didn't put cost saving as an explicit advantage of Vote From Hat, but perhaps I should have).

What's been missed, at least in the commentary I've read so far, is that while the principle that democracy is too expensive is repulsive to most Britons, we do it all the time - not in the choice of vote counting system, but in the operation of our vote collection.

At the last general election, there were several cases of disenfranchisement through underfunding - shortages of ballot papers that would have cost more to print; people being turned away from polling stations because local authorities didn't want to pay enough polling staff to meet the Electoral Commission recommended minimum staffing levels; intentionally using inaccessible polling stations; failing to spend time and money reviewing the accessibility of polling stations and fixing the problems, and so on. For some people with disabilities, the idea that it's not worth paying money to allow them to vote is well established.

I certainly believe that if you're going to have a democracy, you can't then put a maximum price on establishing a universal franchise - you pay the costs happily.

If First Past The Post is to be considered superior to Alternative Vote - a stance I disagree with, of course - it should be on the grounds of its ability to democratically reflect the will of the electorate, not on the grounds of cost. But let's apply that to other areas of electoral administration too, not just the vote counting system.


  1. The Meek variant of Single Transferable Vote, because it recursively adjusts the transfer values to get the optimal result (rather than the near-optimal estimates used by other STV variants), can only be counted by computer. Every other vote counting system I'm aware of, including most STV variants, can be done entirely by hand.

    A computer-assisted count - using generic laptops or desktops the local authority already has to run a spreadsheet or OpenSTV, not expensive specialised hardware - would make things considerably easier for most Single Transferable Vote variants, Borda, and Range Voting, but even that isn't necessary for Alternative Vote.

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Friday, 11 February 2011

Tuesday, 8 February 2011

Quorums and democratic legitimacy

The House of Lords has amended the AV referendum Bill so that the referendum would require the votes of 40% of voters to be binding.

This is extremely anti-democratic, but of course so is the Lords in general, so this is hardly surprising. (For all the Commons' faults, a similar amendment there was resoundingly defeated by cross-party consensus)

The obvious problem with a quorum for any vote where one of the options is to do nothing, is that if the quorum is difficult to reach, it's often more effective for those opposing change to not vote than it is to vote no.

40% will be difficult to reach. Only general elections get that high a turnout in the UK (and then not always in every constituency). If we assume, implausibly, a potential turnout of 60%, comparable with a modern general election, then if at least a third, but less than half, of voters oppose it, they can "win" by collectively not voting.

Lower the turnout further, and it becomes even less possible for a vote for change to succeed.

This does raise the question, of course, of what would be done in a situation where the turnout was good (for a non-general election) but not exceptional - say 20% - almost all of which was in favour of change because most of the status quo voters had stayed home. Parliament - especially the Commons, which voted against the quorum requirement in the first place - would then be under great pressure to pass further legislation to implement it anyway.

I think quorum requirements in general are a really bad idea. They're only useful in a situation where it's plausible that a minority interest group could call a vote with so little publicity and/or notice and/or accessibility that hardly anyone who opposed them knew what was going on, and so a minimum attendance to prevent this is required.

The rest of the time, they're either unachievable, leading to an organisation that can't make changes because it's impossible to get the votes to do it, or they're trivial - ten people out of thousands - and thus rather pointless.

In this situation, it's rather implausible that the referendum could be called without sufficient publicity or notice, and while some of the polling stations will be extremely inaccessible to some voters, that's not an issue that a quorum figure is going to fix.

So, essentially, if the Commons don't amend this back out (and the Lords have filibustered long enough on the Bill that they don't have time for a long argument without delaying the referendum) the vote is certain to fail.

That a narrow majority of the Lords care so much about the electoral system used in an election that they can't even vote in that they're willing to stoop this low to rig the result (rather than campaign for the result they want) is a strong sign that they need replacing with a fully-elected house as soon as possible.

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Monday, 7 February 2011


[trigger warning]

Parliament recently discussed Anna Soubry MP's (Conservative, Broxtowe) Anonymity (arrested persons) Bill, which would have made it a fairly serious offence to report in the press on the arrest of a person who had not yet been charged, except where a court order allowed this.

Various points were raised in the debate, including:

  • the possibility of abuse of this by making it difficult to discover patterns in arrests, or making it difficult to discover that a politically-sensitive arrest had been made;
  • practical difficulties of enforcing this form of reporting when news travels rapidly on the internet, and by gossip within geographic communities, outside of the scope of the press;
  • the risk of legislating in general to cover a problem that affects only a tiny minority of cases;
  • that a token fine is unlikely to dissuade a newspaper, but a custodial sentence for the editor is conversely rather harsh;
  • that it would be difficult to bind foreign media available in the UK, of which there are many.

All relevant points, of course, on both the undesirability and the impracticality of a general ban on this sort of reporting.

Other than the Bill's sponsor, and the Minister (Crispin Blunt MP) responsible for this area of legislation, though, I'm not sure that a single one of the (mostly-male, mostly-coalition) MPs speaking in this debate raised any of those points in any of the previous debates on reporting restrictions in rape cases.

(A pattern mirrored in the internet debate of those proposals, where the usual "free speech"/"freedom of the press" advocates were largely absent from the discussion when it was only about rape cases.)

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Friday, 4 February 2011

Friday Links