Can polls be reliable?

Election polls in many countries have seemed unusually unreliable recently. Why? And can they be fixed?

The most basic observation is that if one has a random sample of a population in which x% has some attribute then it is reasonable to estimate that x% of the whole population has that attribute, and that this estimate will tend to be more accurate the larger the sample is. In some polls sample size can be an issue, but not in the main political polls.

A fundamental problem with most polls is that the ‘random’ sample may not be uniformly distributed, with some sub-groups over or under represented. Political polls have some additional issues, that are sometimes blamed:

  • People with certain opinions may be reluctant to express them, or may even mislead.
  • There may be a shift in opinions with time, due to campaigns or events.
  • Different groups may differ in whether they actually vote, for example depending on the weather.

I also think that in the UK the trend to postal voting may have confused things, as postal voters will have missed out on the later stages of campaigns, and on later events. (Which were significant in the UK 2017 general election.)

Pollsters have a lot of experience at compensating for these distortions, and are increasingly using ‘sophisticated mathematical tools’. How is this possible, and is there any residual uncertainty?

Back to mathematics, suppose that we have a science-like situation in which we know which factors (e.g. gender, age, social class ..) are relevant. With a large enough sample we can partition the results by combination of factors, measure the proportions for each combination, and then combine these proportions, weighting by the prevalence of the combinations in the whole population. (More sophisticated approaches are used for smaller samples, but they only reduce the statistical reliability.)

Systematic errors can creep in in two ways:

  1. Instead of using just the poll data, some ‘laws of politics’ (such as the effect of rain) or other heuristics (such as that the swing among postal votes will be similar to that for votes in person) may be wrong.
  2. An important factor is missed. (For example, people with teenage children or grandchildren may vote differently from their peers when student fees are an issue.)

These issues have analogues in the science lab. In the first place one is using the wrong theory to interpret the data, and so the results are corrupted. In the second case one has some unnoticed ‘uncontrolled variable’ that can really confuse things.

A polling method using fixed factors and laws will only be reliable when they reasonably accurately the attributes of interest, and not when ‘the nature of politics’ is changing, as it often does and as it seems to be right now in North America and Europe. (According to game theory one should expect such changes when coalitions change or are under threat, as they are.) To do better, the polling organisation would need to understand the factors that the parties were bringing into play at least as well as the parties themselves, and possibly better. This seems unlikely, at least in the UK.

What can be done?

It seems to me that polls used to be relatively easy to interpret, possibly because they were simpler. Our more sophisticated contemporary methods make more detailed assumptions. To interpret them we would need to know what these assumptions were. We could then ‘aim off’, based on our own judgment. But this would involve pollsters in publishing some details of their methods, which they are naturally loth to do. So what could be done? Maybe we could have some agreed simple methods and publish findings as ‘extrapolations’ to inform debate, rather than predictions. We could then factor in our own assumptions. (For example, our assumptions about students turnout.)

So, I don’t think that we can expect reliable poll findings that are predictions, but possibly we could have useful poll findings that would inform debate and allow us to take our own views. (A bit like any ‘big data’.)

Dave Marsay


JIC, Syria and Uncertainty

This page considers the case that the Assad regime used gas against the rebels on 21st August 2013 from a theory of evidence perspective. For a broader account, see Wikipedia.

The JIC Assessment

The JIC concluded on 27th that it was:

highly likely that the Syrian regime was responsible.

In the covering letter (29th) the chair said:

Against that background, the JIC concluded that it is highly likely that the regime was responsible for the CW attacks on 21 August. The JIC had high confidence in all of its assessments except in relation to the regime’s precise motivation for carrying out an attack of this scale at this time – though intelligence may increase our confidence in the future.

A cynic or pedant might note the caveat:

The paper’s key judgements, based on the information and intelligence available to us as of 25 August, are attached.

Mathematically-based analysis

From a mathematical point of view, the JIC report is an ‘utterance’, and one needs to consider the context in which it was produced. Hopefully, best practice would include identifying the key steps in the conclusion and seeking out and hastening any possible contrary reports. Thus one might reasonably suppose that the letter on the 29th reflected all obviously relevant information available up to the ends of the 28th, but perhaps not some other inputs, such as ‘big data’, that only yield intelligence after extensive processing and analysis.

But what is the chain of reasoning (29th)?

It is being claimed, including by the regime, that the attacks were either faked or undertaken by the Syrian Armed Opposition. We have tested this assertion using a wide range of intelligence and open sources, and invited HMG and outside experts to help us establish whether such a thing is possible. There is no credible intelligence or other evidence to substantiate the claims or the possession of CW by the opposition. The JIC has therefore concluded that there are no plausible alternative scenarios to regime responsibility.

The JIC had high confidence in all of its assessments except in relation to the regime’s precise motivation for carrying out an attack of this scale at this time – though intelligence may increase our confidence in the future.

The report of the 27th is more nuanced:

There is no credible evidence that any opposition group has used CW. A number continue to seek a CW capability, but none currently has the capability to conduct a CW attack on this scale.

Russia claims to have a ‘good degree of confidence’ that the attack was an ‘opposition provocation’ but has announced that they support an investigation into the incident. …

In contrast, concerning Iraqi WMD, we were told that “lack of evidence is not evidence of lack”. But mathematics is not so rigid: it depends on one’s intelligence sources and analysis. Presumably in 2003 we lacked the means to detect Iraqi CW, but now – having learnt the lesson – we would know almost as soon as any one of a number of disparate groups acquires CW.  Many outside the intelligence community might not find this credible, leading to a lack of confidence in the report. Others would take the JIC’s word for it. But while the JIC may have evidence that supports their rating, it seems to me that they have not even alluded to a key part of it.

Often, of course, an argument may be technically flawed but still lead to a correct conclusion. To fix the argument one would want a much greater understanding of the situation. For example, the Russians seem to suggest that one opposition group would be prepared to gas another, presumably to draw the US and others into the war. Is the JIC saying that this is not plausible, or simply that no such group (yet) has the means? Without clarity, it is difficult for an outsider to asses the report and draw their own conclusion.

Finally, it is notable that regime responsibility for the attack of the 21st is rated ‘highly likely’, the same as their responsibility for previous attacks. Yet mathematically the rating should depend on what is called ‘the likelihood’, which one would normally expect to increase with time. Hence one would expect the rating to increase from possible (in the immediate aftermath) through likely to highly likely, as the kind of issues described above are dealt with. This unexpectedly high rating calls for an explanation, which would need to address the most relevant factors.

Anticipating the UN Inspectors

The UN weapons inspectors are expected to produce much relevant evidence. For example, it may be that even if an opposition group had CW an attack would necessarily lack some key signatures. But, from a mathematical point of view, one cannot claim that one explanation is ‘highly likely’ without considering all the alternatives and taking full account of how the evidence was obtained. It is quite true, as the PM argued, that there will always be gaps that require judgement to span. But we should strive to make the gap as slight as possible, and to be clear about what it is. While one would not want a JIC report to be phrased in terms of mathematics, it would seem that appropriate mathematics could be a valuable aid to critical thinking. Hopefully we shall soon have an assessment that genuinely rates ‘highly likely’ independently of any esoteric expertise, whether intelligence or mathematics.


30th August: US

The US assessment concludes that the attack was by Assad’s troops, using rockets to deliver a nerve agent, following their usual procedures. This ought to be confirmed or disconfirmed by the inspectors, with reasonable confidence. Further, the US claim ‘high confidence’ in their assessment, rather than very high confidence. Overall, the US assessment appears to be about what one would expect if Assad’s troops were responsible.

31st August: Blog

There is a good private-enterprise analysis of the open-source material. It makes a good case that the rockets’ payloads were not very dense, and probably a chemical gas. However, it points out that only the UN inspectors could determine if the payload was a prohibited substance, or some other substance such as is routinely used by respectable armies and police forces.

It makes no attribution of the rockets. The source material is clearly intended to show them being used by the Assad regime, but there is no discussion of whether or not any rebel groups could have made, captured or otherwise acquired them.

2nd September: France

The French have declassified a dossier. Again, it presents assertion and argumentation rather than evidence. The key points seem to be:

  • A ‘large’ amount of gas was used.
  • Rockets were probably used (presumably many).
  • No rebel group has the ability to fire rockets (unlike the Vietcong in Vietnam).

This falls short of a conclusive argument. Nothing seems to rule out the possibility of an anti-Assad outside agency loading up an ISO container (or a mule train) with CW (perhaps in rockets), and delivering them to an opposition group along with an adviser. (Not all the opposition groups all are allies.)

4th September: Germany

A German report includes:

  • Conjecture that the CW mix was stronger than intended, and hence lethal rather than temporarily disabling.
  • That a Hezbollah official said that Assad had ‘lost his nerve’ and ordered the attack.

It is not clear if the Hezbollah utterance was based on good grounds or was just speculation.

4th September: Experts

Some independent experts have given an analysis of the rockets that is similar in detail to that provided by Colin Powell to the UN in 2003, providing some support for the official dossiers. They asses that each warhead contained 50 litres (13 gallons) of agent. The assess that the rebels could have constructed the rockets, but not produced the large quantity of agents.

No figure is given for the number of rockets, but I have seen a figure of 100, which seems the right order of magnitude. This would imply 5,000 litres or 1,300 gallons, if all held the agent. A large tanker truck has a capacity of about 7 times this, so it does not seem impossible that such an amount could have been smuggled in.

This report essentially puts a little more detail on the blog of 31st August, and is seen as being more authoritative.

5th September: G20

The UK has confirmed that Sarin was used, but seems not to have commented on whether it was of typical ‘military quality’, or more home-made.

Russia has given the UN a 100 page dossier of its own, and I have yet to see a credible debunking (early days, and I haven’t found it on-line).

The squabbles continue. The UN wants to wait for its inspectors.

6th September: Veteran Intelligence Professionals for Sanity

An alternative, unofficial narrative. Can this be shown to be incredible? Will it be countered?

9th September: German

German secret sources indicate that Assad had no involvement in the CW attack (although others in the regime might have).

9th September: FCO news conference

John Kerry, at a UK FCO news conference, gives very convincing account of the evidenced for CW use, but without indicating any evidence that the chemicals were delivered by rocket. He is asked about Assad’s involvement, but notes that all that is claimed is senior regime culpability.

UN Inspectors’ Report

21st September. The long-awaited report concludes that rockets were used to deliver Sarin. The report, at first read, seems professional and credible. It is similar in character to the evidence that Colin Powell presented to the UN in 2003, but without the questionable ‘judgments’. It provides some key details (type of rocket, trajectory) which – one hopes – could be tied to the Assad regime, especially given US claims to have monitored rocket launches. Otherwise, they appear to be of  type that the rebels could have used.

The report does not discuss the possibility, raised by the regime, that conventional rockets had accidentally hit a rebel chemical store, but the technical details do seem to rule it out. There is an interesting point here. Psychologically, the fact that the regime raised a possibility in their defence which has been shown to be false increases our scepticism about them. But mathematically, if they are innocent then we would not expect them to know what happened, and hence we would not expect their conjectures to be correct. Such a false conjecture could even be counted as evidence in their favour, particularly if we thought them competent enough to realise that such an invention would easily be falsified by the inspectors.


Initial formal reactions

Initial reactions from the US, UK and French are that the technical details, including the trajectory, rule out rebel responsibility. They appear to be a good position to make such a determination, and it would normally be a conclusion that I would take at face value. But given the experience of Iraq and their previous dossiers, it seems quite possible that they would say what they said even without any specific evidence. A typical response, from US ambassador to the UN Samantha Power was:

The technical details of the UN report make clear that only the regime could have carried out this large-scale chemical weapons attack.”

Being just a little pedantic, this statement is literally false: one would at least have to take the technical details to a map showing rebel and regime positions, and have some idea of the range of the rockets. From the Russian comments, it would seem they have not been convinced.

Media reaction

A Telegraph report includes:

Whether the rebels have captured these delivery systems – along with sarin gas – from government armouries is unknown. Even if they have, experts said that operating these weapons successfully would be exceptionally difficult.

”It’s hard to say with certainty that the rebels don’t have access to these delivery systems. But even if they do, using them in such a way as to ensure that the attack was successful is the bit the rebels won’t know how to do,” said Dina Esfandiary, an expert on chemical weapons at the International Institute for Strategic Studies.

The investigators had enough evidence to trace the trajectories followed by two of the five rockets. If the data they provide is enough to pinpoint the locations from which the weapons were launched, this should help to settle the question of responsibility.

John Kerry, the US secretary of state, says the rockets were fired from areas of Damascus under the regime’s control, a claim that strongly implicates Mr Assad’s forces.

This suggests that there might be a strong case against the regime. But it is not clear that the government would be the only source of weapons for the rebels, that the rebels would need sophisticated launchers (rather than sticks) or that they would lack advice. Next, given the information on type, timing and bearing it should be possible to identify the rockets, if the US was monitoring their trajectories at the time, and hence it might be possible to determine where they came from, in which case the evidence trail would lead strongly to the regime. (Elsewhere it has been asserted that one of the rockets was fired from within the main Syrian Army base, in which case one would have thought they would have noticed a rebel group firing out.)

17 September: Human Rights Watch

Human Rights Watch has marked the UN estimate of the trajectories on a map, clearly showing tha- they could have been fired from the Republican Guard 104 Brigade area.

Connecting the dots provided by these numbers allows us to see for ourselves where the rockets were likely launched from and who was responsible.

This isn’t conclusive, given the limited data available to the UN team, but it is highly suggestive and another piece of the puzzle.

This seems a reasonable analysis. The BBC has said of it:

Human Rights Watch says the document reveals details of the attack that strongly
suggest government forces were behind the attack.

But this seems to exaggerate the strength of the evidence. One would at least want to see if the trajectories are consistent with the rockets having been launched from rebel held areas (map, anyone?) It also seems a little odd that a salvo of M14 rockets appear to have been fired over the presidential palace. Was the Syrian Army that desperate? Depending on the view that one takes of these questions, the evidence could favour the rebel hypothesis. On the other hand, if the US could confirm that the only rockets fired at that time to those sites came from government areas, that would seem conclusive.

(Wikipedia gives technical details of rockets. It notes use by the Taliban, and quotes its normal maximum range as 9.8km. The Human Rights Watch analysis seems to be assuming that this will not be significantly reduced by the ad-hoc adaptation to carry gas. Is this credible? My point here is that the lack of explicit discussion of such aspects in the official dossiers leaves room for doubt, which could be dispelled if their ‘very high confidence’ is justified.)

18 September: Syrian “proof”

The BBC has reported that the Syrians have provide what they consider proof to the Russia that the rebels were responsible for the CW attack, and that the Russians are evaluating it. I doubt that this will be proof, but perhaps it will reduce our confidence in  the ‘very high’ likelihood that the regime was responsible. (Probably not!) It may, though, flush out more conclusive evidence, either way.

19 September: Forgery?

Assad has claimed that the materials recovered by the UN inspectors were forged. The report talks about rebels moving material, and it is not immediately clear, as the official dossiers claim, that this hypothesis is not credible, particularly if the rebels had technical support.

Putin has confirmed that the rockets used were obsolete Soviet-era ones, no longer in use by the Syrian Army.

December: US Intelligence?

Hersh claims that US had intelligence that the Syrian rebels had chemical weapons, and that the US administration  deliberately ‘adjusted’ the intelligence to make it appear much more damning of the Syrian regime. (This is disputed.)


The UN Inspectors report is clear about what it has found. It is careful not to make deductive leaps, but provides ample material to support further analysis. For example, while it finds that Sarin was delivered by rockets that could have been launched from a regime area, it does not rule out rebel responsibility. But it does give details of type, time and direction, such that if – as appears to be the case from their dossier – the US were monitoring the area, it should be possible to conclude that the rocket was actually fired by the regime. Maybe someone will assemble the pieces for us.

My own view is not that Assad did not do it or that we should not attack, but that any attack based on the grounds that Assad used CW should be supported by clear, specific evidence, which the dossiers prior to the UN report did not provide. Even now, we lack a complete case. Maybe the UN should have its own intelligence capability? Or could we attack on purely humanitarian grounds, not basing the justification on the possible events on 21 Aug? Or share our intelligence with the Russians and Chinese?

Maybe no-one is interested any more?

See Also

Telegraph on anti-spy cynicism. Letters. More controversially: inconclusive allegations. and an attempted debunking.

Discussion of weakness of case that Assad was personally involved. Speculation on UN findings.

A feature of the debate seems to be that those who think that ‘something must be done’ tend to be critical of those who question the various dossiers, and those who object to military action tend to throw mud at the dossiers, justified or not. So maybe my main point should be that, irrespective of the validity of the JIC assessment, we need a much better quality of debate, engaging the public and those countries with different views, not just our traditional allies.

A notable exception was a private blog, which looked very credible, but fell short claiming “high likelihood”. It gives details of two candidate delivery rockets, and hoped that the UN inspectors will have got evidence from them, as they did. Neither rocket was known to have been used, but neither do they appear to be beyond the ability of rebel groups to use (with support). The comments are also interesting, e.g.:

There is compelling evidence that the Saudi terrorists operating in Syria, some having had training from an SAS mercenary working out of Dubai who is reporting back to me, are responsible for the chemical attack in the Ghouta area of Damascus.

The AIPAC derived ‘red line’ little game and frame-up was orchestrated at the highest levels of the American administration and liquid sarin binary precursors mainly DMMP were supplied by Israeli handled Saudi terrorists to a Jabhat al-Nusra Front chemist and fabricator.

Israel received supplies of the controlled substance DMMP from Solkatronic Chemicals of Morrisville, Pa.

This at least has some detail, although not such as can be easily checked.

Finally, I am beginning to get annoyed by the media’s use of scare quotes around Russian “evidence”.

Dave Marsay

Systemism: the alternative to individualism and holism

Mario Bunge Systemism: the alternative to individualism and holism Journal of Socio-Economics 29 (2000) 147–157

“Three radical worldviews and research approaches are salient in social studies: individualism, holism, and systemism.”

[Systemism] “is centered in the following postulates:
1. Everything, whether concrete or abstract, is a system or an actual or potential component of a system;
2. systems have systemic (emergent) features that their components lack, whence
3. all problems should be approached in a systemic rather than in a sectoral fashion;
4. all ideas should be put together into systems (theories); and
5. the testing of anything, whether idea or artifact, assumes the validity of other items, which are taken as benchmarks, at least for the time being.”

Thus systemism resembles Smuts’ Holism. Bunge uses the term ‘holism’ for what Smuts terms wholism: the notion that systems should be subservient to their ‘top’ level, the ‘whole’. This usage apart, Bunge appears to be saying something important. Like Smuts, he notes the systemic nature of mathematics is distinction to those who note the tendency to apply mathematical formulae thoughtlessly, as in some notorious financial mathematics

Much of the main body is taken up with the need for micro-macro analyses and the limitations of piece-meal approaches, something familiar to Smuts and |Keynes. On the other hand he says: “I support the systems that benefit me, and sabotage those that hurt me.” without flagging up the limitations of such an approach in complex situations. He even suggests that an interdisciplinary subject such as biochemistry is nothing but the overlap of the two disciplines. If this is the case, I find it hard to grasp their importance. I would take a Kantian view, in which bringing into communion two disciplines can be more than the sum of the parts.

In general, Bunge’s arguments in favour of what he calls systemism and Smuts called holism seem sound, but it lacks the insights into complexity and uncertainty of the original.

See also

Andy Denis’ response to Bunge adds some arguments in favour of Holism. It’s main purpose, though, is to contradict Bunge’s assertion that laissez-faire is incompatible with systemism. It is argued that a belief in Adam Smith’s invisible hand could support laissez faire. It is not clear what might constitute grounds for such a belief. (My own view is that even a government that sought to leverage the invisible hand would have a duty to monitor the workings of such and hand, and to take action should it fail, as in the economic crisis of 2007/8. It is now clear how politics might facilitate this.)

Also my complexity.

Dave Marsay

Science advice and the management of risk

Science advice and the management of risk in government and business

The foundation for science and technology, 10 November 2010

An authoritative summary of the UK governments position on risk, with talks and papers.

  •  Beddington gives a good overview. He discusses probability versus impact ‘heat maps’, the use of ‘worst case’ scenarios, the limitations of heat maps and Blackett reviews. He discusses how management strategy has to reflect both the location on the heat map and the uncertainty in the location.
  • Omand discusses ‘Why wont they (politicians) listen (to the experts)?’  He notes the difference between secrets (hard to uncover) and secrets (hard to make sense of), and makes ‘common cause’ between science and intelligence in attempting to communicate with politicians. Presents a familiar type of chart in which probability is thought of as totally ordered (as in Bayesian probability) and seeks to standardise on the descriptors of ranges of probability, such as ‘highly probable’.
  • Goodman discusses economic risk management and the need to cope with ‘irrational cycles of exuberance’, focussing on ‘low probability high impact’ events. Only some risks can be quantified. Recommends ‘generalised Pareto distribution’.
  • Spielgelhalter introduced the discussion with some important insights:

The issue ultimately comes down to whether we can put numbers on these events.  … how can a figure communicate the enormous number of assumptions which underlie such quantifications? … The … goal of a numerical probability … becomes much more difficult when dealing with deeper uncertainties. … This concerns the acknowledgment of indeterminacy and ignorance.

Standard methods of analysis deal with recognised, quantifiable uncertainties, but this is only part of the story, although … we tend to focus at this level. A first extra step is to be explicit about acknowledged inadequacies – things that are not put into the analysis such as the methane cycle in climate models. These could be called ‘indeterminacy’. We do not know how to quantify them but we know they might be influential.

Yet there are even greater unknowns which require an essential humility. This is not just ignorance about what is wrong with the model, it is an acknowledgment that there could be a different conceptual basis for our analysis, another way to approach the problem.

There will be a continuing debate  about the process of communicating these deeper uncertainties.

  • The discussion covered the following:
    • More coverage of the role of emotion and group think is needed.
    • “[G]overnments did not base policies on evidence; they proclaimed them because they thought that a particular policy would attract votes. They would then seek to find evidence that supported their view. It would be more realistic to ask for policies to be evidence tested [rather than evidence-based.]”
    • “A new language was needed to describe uncertainty and the impossibility of removing risk from ordinary life … .”
    •  Advisors must advise, not covertly subvert decision-making.


If we accept that there is more to uncertainty than  can be reflected in a typical scale of probability, then it is no wonder that organisational decisions fail to take account of it adequately, or that some advisors seek to subvert such poor processes. Moreover, this seems to be a ‘difference that makes a difference’.

From a Keynesian perspective conditional probabilities, P(X|A), sometimes exist but unconditional ones, P(X), rarely do. As Spielgelhalter notes it is often the assumptions that are wrong: the estimated probability is then irrelevant. Spielgelhalter mentioned the common use of ‘sensitivity analysis’, noting that it is unhelpful. But what is commonly done is to test the sensitivity of P(X|y,A) to some minor variable y while keeping the assumptions, A. fixed. What is more often (for these types of risk) needed is a sensitivity to assumptions. Thus, if P(X|A) is high:

  • one needs to identify possible alternatives, A’, to A for which P(X|A’) is low, no matter how improbable A’ may be regarded.


  • ‘Possible’ means consistent with the evidence rather than anything psychological.
  • The criteria for what is regarded as ‘low’ or ‘high’ will be set by the decision context.

The rationale is that everything that has ever happened was, with hind-sight, possible: the things that catch us out are those that we overlooked, perhaps because we thought them improbable.

A conventional analysis would overlook emergent properties, such as booming cycles of ‘irrational’ exuberance. Thus in considering alternatives one needs to consider potential emotions and other emergencies and epochal events.

This suggests a typical ‘risk communication’ would consist of an extrapolated ‘main case’ probability together with a description of scenarios in which the opposite probability would hold.

See also

mathematicsheat maps, extrapolation and induction

Other debates, my bibliography.

Dave Marsay


All watched over by machines of loving grace


An Adam Curtis documentary shown on the BBC May/June 2011.


The trailers (above link) give a good feel for the series, which is entertaining, with some good video, music, pseudo-history and comment. The details shouldn’t be taken too seriously, but it is thought-provoking, on some topics that need thought.


The series ends:

The idea that human beings are helpless chunks of hardware controlled by software programs written in their genetic codes [remains powerfully influential in our society]. The question is, have we embraced that idea because it is a comfort in a world where everything that we do, either good or bad, seems to have terrible unforeseen consequences? …

We have embraced a fatalistic philosophy of us as helpless computing machines, to both excuse and explain our political failure to change the world.

This thesis has three parts:

  1. that everything we do has terrible unforeseen consequences
  2. that we are fatalistic in the face of such uncertainty
  3. that we have adopted a machine metaphor as ‘cover’ for our fatalism.


The program demonizes unforeseen consequences. Certainly we should be troubled by them, and their implications for rationalism and pragmatism. But if there were no uncertainties then we could be rational and ‘should’ behave like machines. Reasoning in a complex, dynamic world calls for more than narrowly rational machine-like calculation, and gives purpose to being human.


It seems reasonable to suppose that most of the time most people can do little to influence the factors that shape their lives, but I think this is true even when people can perfectly well see the likely consequences of what is being done in their name. What is at issue here is not so much ordinary fatalism, which seems justified, as the charge that those who are making big decisions on our behalf are also fatalistic.

In democracies, no-one makes a free decision anymore. Everyone is held accountable and expected to abide by generally accepted norms and procedures. In principle whenever one has a novel situation the extant rules should be at least briefly reviewed, lest they lead to ‘unforseen consequences’. A fatalist would presumably not do this. Perhaps the failure, then, is not to challenge assumptions or ‘kick against’ constraints.

The machine metaphor

Computers and mathematicians played a big role in the documentary. Humans are seen as being programmed by a genetic code that has evolved to self-replicate. But evolution leads to ‘punctuated equilibrium’ and epochs.  Reasoning in epochs is not like reasoning in stable situations, the preserve of rule-driven machines. The mathematics of Whitehead and Turing supports the machine-metaphor, but only within an epoch. How would a genetically programmed person fare if they move to a different culture or had to cope with new technologies radically transforming their daily lives? One might suppose that we are encoded for ‘general ways of living and learning’ but then that we seem to require a grasp of uncertainty beyond that which we currently associate with machines.


  • The program had a discussion on altruism and other traits in which behaviours might disbenefit the individual but advantage those who are genetically similar over others. This would seem to justify much terrorism and even suicide-bombing. The machine metaphor would seem undesirable for reasons other than its tendency to fatalism.
  • An alternative to absolute fatalism would be fatalism about long-term consequences. This would lead to a short-term-ism that might provide a better explanation for real-world events
  • The financial crash of 2007/8 was preceded by a kind of fatalism, in that it was supposed that free markets could never crash. This was associated with machine trading, but neither a belief in the machine metaphor nor a fear of unintended consequences seems to have been at the root of the problem. A belief in the potency of markets was perhaps reasonable (in the short term) once the high-tech bubble had burst. The problem seems to be that people got hooked on the bubble drug, and went into denial.
  • Mathematicians came in for some implicit criticism in the program. But the only subject of mathematics is mathematics. In applying mathematics to real systems the error is surely in substituting myth for science. If some people mis-use mathematics, the mathematics is no more at fault than their pencils. (Although maybe mathematicians ought to be more vigorous in uncovering abuse, rather than just doing mathematics.)


Entertaining, thought-provoking.

Dave Marsay

AV: Yes or No? A comparison of the Campaigns’ ‘reasons’

At last we have some sensible claims to compare, at the Beeb. Here are some comments:

YES Campaign

Its reasons

  1. AV makes people work harder
  2. AV cuts safe seats
  3. AV is a simple upgrade
  4. AV makes votes count
  5. AV is our one chance for a change

An Assessment

These are essentially taken from the all-party Jenkins Commission. The NO Campaign rejoinders seem to be:

  1. Not significantly so.
  2. Not significantly so.
  3. AV will require computers and £250M to implement (see below).
  4. AV Makes votes count twice, or more (se below).
  5. Too right!

A Summary

Worthy, but dull.

An Addenda

I would add:

  • There would be a lot less need for tactical voting
  • The results would more reliably indicate people’s actual first preferences
  • It would be a lot easier to vote out an unpopular government – no ‘vote splitting’
  • It would make it possible for a new party to grow support across elections to challenge the status quo.
  • It may lead to greater turnout, especially in seats that are currently safe

NO Campaign Reasons

AV is unfair


“… some people would get their vote counted more times than others. For generations, elections in the UK have been based on the fundamental principle of ‘one person, one vote’. AV would undermine all that by allowing the supporters of fringe parties to have their second, third or fourth choices counted – while supporters of the mainstream candidates would only get their vote counted once.”


According to the Concise OED a vote is ‘a formal expression of will or opinion in regard to election of … signified by ballot …’ Thus the Irish, Scottish, Welsh, Australians, who cast similar ballots to AV, ‘have one vote’. The NO Campaign use of the term ‘counted’ is also confusing. The general meaning is a ‘reckoning’, and in this sense each polling station has one count per election, and this remains true under AV. A peculiarity of AV is that ballots are also counted in the sense of ‘find number of”. (See ‘maths of voting’ for more.)


There is no obvious principle that requires us to stick with FPTP: all ballots are counted according to the same rules.

Should ‘supporters of fringe parties’ have their second preferences counted? The ‘fringe’ includes:

  • Local candidates, such as a doctor trying to stop the closure of a hospital
  • The Greens
  • In some constituencies, Labour, LibDem, Conservative.

AV is blind to everything except how voters rank them. Consider an election in which the top three candidates get 30%, 28%, 26%, with some also-rans. According to the NO campaign the candidate with a narrow margin should be declared the winner. Thus they would disregard the preferences of anyone who votes for their hospital (say). Is this reasonable?

AV is not widely used

True-ish, but neither is FPTP (in terms of countries – one of them is large), and variants of AV (IRV, STV, …) together are the most widely used.

AV is expensive

Countries with AV don’t have election machinery. Australian elections may cost more than ours, but it is a much bigger country with a smaller population. 

AV hand more power to politicians

See the Jenkins Commission.

AV supporters are sceptical

Opposition to FPTP is split between variants of AV, with single-member constituencies and forms of PR. The Jenkins Commission recommended AV+, seeking to provide the best of both. The referendum is FPTP and hence can only cope with two alternatives: YES or NO.

I don’t know that AV supporters are sceptical against a move away from FPTP – just differ on what would be ideal.


  • The NO campaign is playing down the ‘strong and stable government’ argument. The flip side is that an unpopular government can survive.
  • A traditional argument for FPTP was that it encourages tactical voting and hence politicking, and hence develops tough leaders, good at dealing with foreigners. We haven’t heard this, this time. Maybe the times are different?

See Also

AV or FPTP, according to wikipedia and Jenkins

The choice: FPTP or AV?

The UK has this choice on May 5th. (AV is also known as Instant Runoff Voting.) The debate so far hasn’t been particularly enlightening. Here I consider the advice from wikipedia and the UK Jenkins Commission, with a short note on tactical voting.


Wikipedia gives a comparison of AV to other voting systems. We are interested in FPTP, a variant of plurality voting. Wikipedia has a table  showing that both methods are about equally common. But which is best?

Advantages of FPTP

Wikipedia shows the following advantages for FPTP:

  • Preservation of “one person, one vote” principle.
  • Moderation
  • Fewer minority parties.

It notes that IRV (AV) is also generally regarded as satisfying ‘one  person one vote’, so this can be discounted. The other two are partially true, but one needs to consider the whole truth.

The UK ‘No’ campaign makes a number of other claims, but they don’t seem to have any validity.


Wikipedia notes:

Under a first-past-the-post system, voters are often afraid of “wasting” their vote on a candidate unlikely to win, so they cast their vote towards their most preferable choice possible of victory. Advocates of plurality voting suggest that this results in most candidates having to field a fairly moderate or centrist position.

This suggests that a moderate or centrist result is desirable. Where FPTP relies on tactical voting (which seems not to be so very common) to achieve this, AV tends to achieve it by design. It also achieves what wikipedia calls the mutual majority criterion. This is quite technical, but links to the notion of majority rule.

Majority rule

Majority rule is the binary decision criterion that if most people prefer A to B then A will be selected. For three or more choices all deterministic methods are technically vulnerable to tactical voting, so one needs to decide which desiderata are essential, and which can be compromised.

Suppose that one has a tribal society with the biggest tribe commanding 26% of the vote using its majority to repress the other tribes. Suppose that all other tribes would prefer a representative from anything other than the biggest tribe. Then majority rules demands that they get one. But if all tribes put up a candidate then the biggest tribe may win, due to vote splitting.

 AV is not liable to vote-splitting and respects the mutual majority criterion, and hence is ‘democratic’ in a different (fuller?) sense than FPTP where it seems to be considered a virtue that the opposition parties must form a pre-election agreement on a common candidate.

Fewer minority parties

FPTP encourages both tactical voting and strategic agreement, coalitions or unions of parties, to avoid gross vote splitting. This leads to fewer minority parties, either because tactical voters don’t vote for them or because they merge with other parties. Under AV voters can vote for a minority party without wasting their vote. Voting will also generally be less tactical, and thus, unlike FPTP, a minority is not disadvantaged in building to a majority over a series of elections.

Summary from FPTP perspective

FPTP rewards politicking and ‘strong parties’ by rewarding tactical voting and pre-election agreements between candidates or parties. It disadvantages minority parties, such as the UK Greens and BNP. Are these good things?

Under FPTP a minority party which was most voter’s last choice could gain or retain power by ‘divide and rule’. Is this a problem?

Advantages of AV

Wikipedia notes many advantages of AV, including the mutual majority criterion. It has this special case:

Instant-runoff voting [aka AV] also passes the Condorcet loser criterion, which requires that if a candidate would lose a head-to-head competition against every other candidate, they must not win the overall election. First-past-the-post does not meet this criterion, indeed it is usually violated in elections with more than two popular candidates.

Tactical voting

All methods are vulnerable to tactical voting,  so some compromise is required. Under FPTP vote-splitting can encourage you to vote tactically to avoid your worst-case choice winning. Wikipedia notes that, while not perfect, “alternative vote is quite resistant to strategy” (i.e., tactical voting). Under AV you are encouraged to vote tactically when:

  • There are preferences that form a cycle, as in AB, BC, CA.
  • You can be sure that the other candidates’ supporters aren’t voting tactically, or if they are, what proportion is voting tactically, and how.

The first condition is normally considered rare, and is where all methods have a problem. The second makes tactical voting much more risky: whereas under FPTP tactical voting is usually straightforward, under AV it is for from this.

Jenkins Commission

The UK’s Jenkins Commission took a broad of the political implications of FPTP versus AV and others. The defects of FPTP were:

  • A tendency to result in landslides.
  • Disadvantages third parties, even strong ones.
  • Disadvantages parties with even support across constituencies.
  • The essential contest is fought over a few ‘marginal’ seats.
  • It leads to ‘perverse’ results.
  • It advantages the ruling party.

The report noted the above advantages. Further:  

Fairness to voters is the first essential. A primary duty of an electoral system is to represent the wishes of the electorate as effectively as possible. The major ‘fairness’ count against First Past the Post is that it distorts the desires of the voters. That the voters do not get the representation they want is more important than that the parties do not get the seats to which they think they are entitled.


It [AV] would also virtually ensure that each MP commanded at least majority acquiescence within his constituency, which is far from being the case under FPTP, where as we have seen nearly a half of members have more opponents than supporters, and, exceptionally, a member can be elected (as in Inverness in 1992) with as little as 26% of the vote.

There were no criticisms of AV at the constituency level. The most significant criticism was that it isn’t proportional. AV is not always any more proportionate than FPTP, but this is not at issue in the UK referendum. In any case, some people prefer methods that tend to lead to enhanced majorities.


Wikepedia seems to provide a relatively independent summary of voting systems, including the unavoidable problems and the pros and cons of FPTP and AV (aka IRV) considered across many countries and years. A comparison with the UK’s current YES and NO campaigns seems instructive: not everything they say should be taken at face value.

One way to decide would be to rate yourself on the following scales:

  1. We need a system that gives the sitting candidate / party an advantage … or not.
  2. We need a system that gives the two leading candidates / parties an advantage … or not.
  3. We need a system that discriminates against minority parties such as the BNP … or we don’t want to discriminate against parties like the Green party.
  4. We want a system that tends to leave us with the same old two main parties … or we want a system that allows new parties to grow and potentially overtake the old parties, as long as they have support.
  5. We want a system that rewards politicking  and tactical voting … or not.
  6. We want every vote to be counted once (in a technical sense) … or we want to make sure that votes are not split.
  7. We want a system that tends to stable government, by giving the ruling party an advantage … versus we want a system that will enable us to oust the ruling party when the majority wish to do so.
  8. We want the winner to have the most first preferences … or we want to reject every candidate that belongs to a group such that some majority prefers all of those outside the group to all of those inside (as in the criterion above).

Of these alternatives, the first would indicate FPTP, the second AV. Another way to choose is to think about the current situation. If the government does well the Conservatives are likely to get a working majority next time. If the government does badly then labour should do well. The voting system should only affect things if the government performance is debatable, so if you support one of the major parties then the voting system will not matter unless your party’s policy turns out to be wrong. What might favour the liberals? If the coalition does okay and many floating voters think that it could have gone much worse without the liberals’ moderating influence. Thus, if the liberals’ manifesto was essentially correct they might do better than last time, more so under AV. This could be seen to be reasonable. I can’t think of a credible situation in which AV favours a party whose manifesto ‘line’ was clearly wrong. The longer term impacts, such as suppressing the BNP and the Greens, seem more significant. For example, labour might split into ‘new’ and ‘old’, allowing the electorate to choose. similarly, if the government does badly the Conservatives might split into ‘wet’ and ‘dry’, giving voters a choice. Under FPTP the two main parties are effectively coalitions with only party members choosing the ‘flavour’. AV would give others a say, which would presumably be a moderating influence. Which is more reasonable?

Which of all these considerations is more important? My current view is that:

  •  AV better respects the wishes of the majority
  • FPTP encourages tactical voting
  • AV gives candidates which have a lot of first preferences some advantage over ‘wishy washy’ candidates that are ranked reasonably high by most but which are the first preference of few. This is not as much of factor as for FPTP, but seems reasonable.

See also

David Marsay