Posts Tagged New Zealand

NZ (Nearly) Tops Skeptics Chart Darcy Cowan Jan 20


Just in my RSS feed is this post on the SkepticBlog site talking about the number of page views of the blog ranked by country. The stats are adjusted and represent page views per million of the country’s population.

New Zealand follows Canada in the #1 spot relegating the US to #3. HA.

What’s the deal? Why are we so over represented?

I’d like to say it’s because our population is just highly educated and naturally receptive to the sceptical mind set.

Any suggestions?

Page Views of "Skepticblog" per million Ranked by Country

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Filed under: Sciblogs, skepticism Tagged: New Zealand, Science and Society, SkepticBlog, skeptics

God, UFOs, Life After Death: What do New Zealanders Believe? Darcy Cowan Dec 07

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Reading the paper today I learned that 1/3 of New Zealanders believe that we have been visited by extra terrestrials. I thought this was an interesting juxtaposition of stories given that a page or two later there was a report about a possibly habitable planet. Maybe aliens are visiting us from Kepler-22b.

Keplerites aside, I decided to look up the report from UMR Research about the beliefs of my fellow citizens.

The report makes for interesting reading (if somewhat disconcerting in places) and I’ll be looking for the follow-up reports around Maori culture and Herbal remedies. The first thing to note is that this was an on-line survey, so right off we should be wary about how representative these findings are of the general population. In that vein there was some attempt to make the results as representative as possible with quotas and weighting of responses. I couldn’t find details of how this was carried out so with that in mind do take the results with a grain of salt.

One of the first things that jumped out at me was how uncertain people were regarding their answers. The questions seems to have 4 possible answers for both the affirmative and negative, from Absolutely Certain through Fairly Certain, Not Too Certain and Not At All Certain.

So while 61% believe “That there is a God or some sort of universal spirit” only 28% are absolutely certain of this. If we lump in the fairly certains then it goes to 41% (from now on I’ll consider both groups to make up the “Certain” category). Compared to 38% who don’t believe (27% of who are certain-ish). 38% non-believers in NZ. It’s difficult to compare data sets but this appears to be up somewhat from ~34% (depending on how you count) religiously unaffiliated at the 2006 Census.

57% of us believe that there is life after death. 32% are certain. 31% are certain this isn’t the case. 55% of us believe in psychic powers, 27% are certain; 27% are certain that they don’t exist.

Now we get to the headline grabbing UFO question. 33% believe we have been or are being visited. How many are certain? 11%.

That’s a bit of a relief.

Then there’s Astrology. 24% think there is something to that malarkey. Only 6% are certain though. Whew…That’s lucky. Still, those horoscopes are everywhere.

It seems that the hardcore believers tend to only make up a minority of the population, even for the mainstream beliefs. With the more mainstream the belief the more evenly spilt the believers and non-believers. i call that interesting. As well as somewhat heartening.

The report breaks down the results further into gender and ethnic responses but I’m happy with looking at the top level stuff here. Check it out to see how women answered differently than men and how ethnicities are split between the different questions.

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Filed under: Psychic Phenomena, Psychological, Religion, Sciblogs, Science Tagged: belief, New Zealand, nz, Religion and Spirituality, sceptic, Science and Society, skeptic

Thoughts About Taniwhas Darcy Cowan Jun 14

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This is probably a very ill considered post. I do feel compelled to write something on this subject however.

Today in the NZ Herald Kepa Morgan has a piece relating why we should listen when Maori raise concerns regarding respect for the traditional dwelling places of Taniwha. I think he raises a very good point that the imagery of Taniwha may be used in place of real and complex issues that may impact any proposed civil engineering project. Unfortunately I disagree that this means that any concerns must therefore be automatically be taken seriously and addressed.

Mr Morgan raises valid points about subsequent real damage that might have afflicted the State Highway that was re-routed due to a Taniwha and actual damage sustained by the Ngawha Prison complex. In each case though this is post hoc reasoning – in hindsight we should have listened to these concerns because something bad happened after we did or didn’t.

This has no bearing in the legitimacy of the claims as they were stated at the time, or in the current case. Yes, the Taniwha may represent potential material issues that affect building projects but framing the issues in this way adds absolutely nothing to the discussion. We could substitute any number of supernatural beings into the claim, such as fairies  or leprechauns or even gremlins[1] and the informational content would remain unchanged.

Were the claims to be brought forward in terms that civil engineers could understand and address then we could engage in a ration discussion about the pros and cons of proceeding as planed. As it stands, this is impossible. We can either accept the claims at face value and bow to, at best, poorly articulated real concerns and at worst blind superstition. Or we can carry on oblivious and be labelled culturally insensitive.

Neither of these options appear particularly enticing to me.

Kepa observes:

“If the initiative had allowed a more thorough investigation of tangata whenua concerns, it is possible the current situation may have been avoided. “

I agree, in theory. In practice though how much effort should be expended investigating these concerns from every possible angle without any supporting evidence or even any suggestion of where we should focus our attention?

Further he notes:

“…in most cases the information that engineers are relying on to make decisions is incomplete and fallible.

Therefore it is prudent to take into account all sources of knowledge, rather than assuming that a poorly informed mono-cultural understanding of an issue is the only one that really matters. “

Again, agreed – but how do vague concerns about a mythical creature increase the amount of knowledge engineers have to work with?

Cultural sensitivity is not my strong suit[2], but it seems to me such issues need to be moved past before a truly productive and mutually respectful dialogue can take place.

Or I could be wrong.[3]


1. Where’s William Shatner when you need him?

2. Heck, I don’t even care about my “own” culture, whatever that is.

3. Please school me, I readily admit these things often pass me by.

[Edit: Just noticed that the wrong link was put in, the wordpress link dialog has been causing  me issues. Apologies]

Filed under: Psychological, Religion, Sciblogs, Science, skepticism Tagged: Environment and Ecology, Herald, Kepa Morgan, New Zealand, New Zealand Herald, nz, NZ Herald, rail, Science and Society, taniwha

MOONQUAKE: What Does the Science Say? Darcy Cowan Mar 03


As usual I’m late for the bandwagon, hey, guys, wait up! Ok, so David Winter over at The Atavism has already compared Ken Ring’s predictions to the actual data around the latest quake and done an excellent job[1]. Several other Scibloggers have also contributed articles around this topic (1,2,3,4)[2], hopefully I can provide a slightly different angle.

After the interview with Ken Ring on Tuesday I received a phone call from a mate about Ken’s hypothesis and we had an interesting discussion about the nature of science and the plausibility that one guy is right and an entire field of scientists is wrong. I felt it was low, in the spirit of egalitarianism he (and I suspect many others in the community) thought it was worth taking seriously. One thing that came up was the possibility that the world community of seismologists has completely ignored any effect that the moon might have on earthquake activity.

On the face of things the proposal that the moon has an effect on the Earth’s crust is uncontroversial. After all tides in the worlds oceans is a direct effect of the Moon’s (and Sun’s) gravity on the massive body of water encircling out globe. Indeed the crust of the Earth does also move due to the Moon, up to 0.5 meters. It is also known that tidal forces can inject large amounts of energy into a celestial body. So the suggestion that the Moon could put stress on the faultlines of the Earth and trigger earthquakes is not necessarily far-fetched.

Reasonable conjecture has now played its part, we have identified what appears to be a reasonable hypothesis now we must make predictions and collect data we can use to test those predictions.

Unfortunately for Ken and his supporters even a cursory examination of the literature shows that this is a question that has been looked at many  times over at least the last 45 years[3,4,5,6] and further back than than 100 years[7]. Each time the results have been either negative or shown an increase in frequency of earth quakes so small as to be useless as a predictive guide[6].

Data has been collated from thousands (or hundreds of thousands) of earthquake events at various faultlines around the world over decades worth of recorded data. Were there to be a significant correlation between earth tidal forces caused by the Moon (or the Earth/Moon/Sun system for some analyses) then this would have been evident from the published data. That scientists would keep this quiet merely in order to ridicule Ken (or keep the status quo or retain funding or whatever the current conspiracy theory is) simply begars belief.

This is a mind set reminiscent of the alternative medicine crowd or the cold fusion fringe. That “Scientists”[8] are dogmatic, grant chasing, self important and self aggrandising puppets of the NWO seems to be a recurring theme when evidence doesn’t go their way. If this method of predicting earthquakes held up to scrutiny then thousands of lives could be saved, surely only the most far-gone of conspiracy theorists can convince themselves that the scientific community is this indifferent to human life.

In conclusion-  Scientists: 1 ; Ken Ring: 0.



1. Go there now, it’s much more interesting than what follows.

2. As above note, and if I’ve missed any – sorry.

3. Simpson, John F. (1967) Earth tides as a triggering mechanism for earthquakes, John F.
Earth and Planetary Science Letters
Volume 2, Issue 5, August 1967, 473-478

4. Hartzell, S. H., and Heaton, T. H. (1989). The fortnightly tide and the tidal triggering of earthquakes.
Bulletin of the Seismological Society of America 79, 1282-1286.

5. Vidale, J. E., Agnew, D. C., Johnston, M. J. S., and Oppenheimer, D. H. (1998). Absence of earthquake correlation with Earth tides: An indication of high preseismic fault stress rate. Journal of Geophysical Research 103, 24567-24572.

6. Kennedy, M., Vidale, J. E., Parker, M.G. (2004). Earthquakes and the Moon; Syzygy Predictions Fail the Test
Seismological Research Letters; September/October 2004; v. 75; no. 5; p. 607-612

7. Schuster, A. (1897). On lunar and solar periodicities of earthquakes.
Proceedings of the Royal Society of London 61, 455-465.
Reference from “Earthquakes and the Moon; Syzygy Predictions Fail the Test” footnote #6

8. Scare quotes as these people are obviously referring to figments of their imagination, instead of real live human beings not unlike themselves. An impersonal boogyman is what is required.


[EDITED: 3/3/11 16:44pm, for my poor grammar]

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Filed under: Questionable Techniques, Sciblogs, Science Tagged: Christchurch, Crust (geology), Earth, Earth Sciences, Earthquake, Ken Ring, Moon, New Zealand, pseudoscience

’Mantrol’ and the Psychology of Destructive Behaviour Darcy Cowan Nov 18


Recently the NZ Transport Authority and the Police introduced a new campaign for reducing driver speeding. The “Mantrol” concept attempts to link the safe driving with “manliness” and in this way induce those who might speed out of machismo to take a second look at what constitutes that ever mercurial definition of “real man”.

Looking at a few of the comments on the Stuff version of this story there is a lot of negativity regarding this campaign. I think many of the comments miss the point. I agree many of the comments (in aggregate) that auto fatalities are a multi-factorial problem, not only speed but driver competency, road condition, alcohol, culture, road laws etc are all contributing to the current situation. To expect one ad campaign to address all of these disparate causes is obviously unrealistic. It is even unrealistic to expect one campaign to address and counter every reason that a person might speed. We have had the graphic advertisements showing the consequences of out of control speeding, these will work on one sub-set of the population. Now we have an approach that may have an effect on a different sub-set.

I wrote in January about a study comparing types of cigarette warnings, the study found that warnings emphasising mortality were less effective on individuals who based their self esteem, at least in part, on their smoking behaviour. As a result those individuals would rate themselves as more inclined to continue smoking. On the other hand, warnings that directly attack the source of self esteem are more effective. Individuals who consider smoking to make them more attractive (the “coolness” factor) will be more influenced by warnings that state the opposite.

One of the conclusions of the study was that warnings may need to be tailored to the population you are trying to influence.The depending factor is how much the behaviour is related to a person’s self esteem and self image.

In attempting to tie safe driving to manliness there is a move towards reaching people at a place in their psyche that relates to their self esteem and how that manifests in their behaviour. In other words if speeding is an expression of one of a person’s core beliefs about themselves ie that they are macho man, then pointing out that in the eyes of others their behaviour is inconsistent with that label may lead to a behavioural change.

Now I do think that the current set of ads don’t quite hit that mark but I do think that they are a step in the right direction. The implicit humour of the ads are also a mark in their favour but they are perhaps a little too close in flavour to a number of other ads currently in the market (multitude of beer ads, even McDonalds ads) trying to tie their product to what real manly men do.

In any event, it is too early to tell whether or if the current crop of anti-speeding ads will have an effect on behaviour. I do think that the use of multiple approaches is valuable in itself as a one-size-fits-all attempt is certainly doomed to failure.

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Filed under: Psychological, Sciblogs Tagged: Behavior, Defensive driving, health, New Zealand, Science and Society, Self-esteem, Traffic collision

Vaccination Awareness Week Round-Up Darcy Cowan Nov 05

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There’s still officially one more day of Anti-Vaccine Awareness Week (two really, as it’s an American idea) but here’s a round up of the posts anyway. While I know there are lots of great in-depth posts around the blogosphere on this the following list has been restricted to NZ posts to keep the local flavour. The posts are in roughly chronological order.

The University of Auckland Library at Tamaki Library blog Misinformation spread about HPV vaccine

Me Anti-Vaccination in NZ

Scott at Imperatorfish They Can’t Vaccinate Against Tin-Foil Hat Syndrome

Michelle at Skeptics In The Pub Vaccines: The actual facts (well, the links to some anyway…)

Alison Campbell at Bioblog on polio

Michelle at Skeptics In The Pub More facts about vaccines….

Me A Side Benefit of the ‘Flu Vaccine — Reduction in Heart Attacks

Michael Edmondsat Sciblogs Guest Work ’I’m not a Scientist but …’; Dissection of an antivaxxer’s argument

Alison Campbell at Bioblog chelation quackery around vaccination

Grant Jacobs at Code for Life Immunisation, then and now

Alison Campbell at Bioblog homeopathic vaccinations — fail

The next couple are not specifically about vaccination but I think are worth a mention:

Grant Jacobs at Code for Life If presenting a claim on a popular issue

Megan Leask at Southern Genes This Week in Science History: 1-11-10

If anyone knows of a post I’ve missed then please feel free to add it in the comments.

[Edit] One more – Alison @ Bioblog vaccination & smallpox

For those of you interested in the international posts, blogger Liz Ditz has done an awesome job collating all of the posts here:

The Big List of Reality-Based Vaccine & Infectious Disease Blogging

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Filed under: Alternative medicine, Medicine, Sciblogs, Science, skepticism Tagged: antivaccinationist, antivaccine, antivax, Health and Medicine, HPV vaccine, Infectious disease, Influenza vaccine, New Zealand, Science, Vaccination, Vaccine, Vaccine controversy

Anti-Vaccination In NZ Darcy Cowan Nov 01


As promised here’s my first entry for “Vaccine Awareness Week”, I thought I would take a little look at Anti-vaccination in New Zealand. In particular the  Immunisation Awareness Society. This organisation has set itself up as pro-choice on the subject of vaccination but this is essentially a thin smokescreen for their anti-vaccination views. Here, rather than pick apart a certain piece of writing from their website (of which there is much to choose from) I’ll focus on the points they have put forward as their basic philosophies and see how they stand up. Without further ado, once more into the breach…

1. That natural immunity is far superior to artificial immunity.

This is true, but only for a given value of “Better”. If you are concerned with antibody production and response to infection over your life time then yes, often immunity acquired via infection by a pathogen can last longer than that stimulated by vaccination.  One reason for this is that if you live in an area where vaccine uptake is relatively low (because, you know, they are so harmful) then you will be periodically re-exposed to the pathogen which naturally boosts your immune response. Vaccine induced immunity does tend to wane over the years and if your only contact with antigens (those parts of the pathogen that promote antibody production) is via the Vaccine then the only way to combat this is a booster shot.

Therefore, to benefit from this longer lasting immunity you must actually contract the disease. You must then also suffer through the consequences and complications of that disease. Then you must be periodically re-exposed to the disease to keep antibody production high. Those that survive will have superior immunity to those who don’t, I believe it’s called “thinning the herd”.

I also notice some weaselling in the reference to artificial immunity.  It is not the immunity that is artificial but the method of inducing immunity. This may seem like splitting hairs but how we use words affects how those words are understood, by implying that the immunity gained by vaccines is itself artificial this group is subtly undermining how vaccines are perceived. Then again the rest of the website is as subtle as a sledgehammer to the face so…

2. That breast milk is the best immune stimulator for the baby during the first year of life and that a great deal of immunological protection is provided to the child for as long as breastfeeding continues.

That’s fine, I agree that breast feeding has undeniable benefits, but unless you intend to breast feed your child for life, making for the creepiest business lunch ever*, your child will eventually need to acquire immunity in some other fashion. In this instance, see above.

3. That good health, which starts with a balanced diet that includes important vitamins and minerals, is safer, and more effective at preventing many diseases than artificial immunity.

I can’t argue that a balanced diet isn’t good for you, there is good evidence that ensuring your body has the vitamins it needs does improve your immune response to infection. Beyond this diet is not a replacement for acquired immunity, once again vaccination is the best method of acquiring immunity without actually having to contract and suffer the disease itself.

4. That appropriate allopathic (conventional) and homoeopathic/naturopathic treatment in the event of illness is safer and more effective than trying to prevent illness through artificial immunity.

Homeopathy is not a treatment for anything besides thirst. Apart from that , treating the disease is safer than not contracting the disease in the first place? Are you kidding me? So not only do you have to contract the disease and chance any side effect of the disease itself but also any complications from treating the disease. Seems to me it’s better to just sidestep the whole issue and not get sick.

5. That most diseases contracted by a healthy child, at an appropriate age in childhood, provide important challenges to the immune system enabling it to mature and strengthen, and almost always provide lifelong immunity to the disease.

I’m so glad that the potentially life threatening  diseases contracted by children are actually good for you. Whatever doesn’t kill you makes you stronger right? How about Measles, that’s one of the dreaded vaccinations our children now receive, what does the WHO have to say about it’s safety?:

Complications: Up to 75% children may develop complications which include diarrhoea, otitis media,
pneumonia, laryngo-tracheal bronchitis (croup) and encephalitis. Measles also depletes Vitamin A status that
results in severe eye complications and blindness. Measles can lead to longer term brain damage and deafness.

Death: Case—fatality ratios for children under one in emergency settings: 3—30%. The three major causes of
high case—fatality rates are pneumonia, diarrhoea and croup. Children may also die from measles infection or
its sequelae including encephalitis and malnutrition. Measles infection often leads to a prolonged suppression
of the immune system, increasing susceptibility to secondary bacterial and viral infections.

But at least we get life long immunity. Surely the purpose of immunity is to prevent us from getting the disease, in that case a wide vaccination policy will do the same thing and also gives us a chance to wipe out the disease altogether.

Then there is the “important challenges” bit, the number of antigens children are exposed to as part of the vaccine schedule is minuscule compared to the number that they are exposed to every day just interacting with their environment. Our normal body flora, those bacteria that call our skin and gut home, outnumber the cells that we would normally think of as “us” by a factor of 10 or more.

This represents hundreds of different species of organisms, add to that the numbers of bacteria we might come into contact with due to food, dirt, household and public surfaces etc. and the number of antigens represented by the organisms prevented by the vaccine schedule can be seen in their proper context – insignificant. Not just insignificant but not even worth mentioning.

6. That the vast majority of childhood infections are benign and self limiting in a healthy, well-nourished, well cared for child with a healthy immune system.

This must mean that the organisation supports vaccination for those diseases that are life threatening (I couldn’t find any evidence on the website that this is the case though). Say pertussis, or Whooping cough as it is more commonly known (from Wikipedea):

Pertussis is fatal in an estimated one in 100 infants under 6 months, and fatal in one in 200 infants aged 2 to 12 months. Infants under one are also more likely to develop complications (eg pneumonia (20%), encephalopathy, seizures (1%), failure to thrive, and death (0.2%)). Pertussis can cause severe paroxysm-induced cerebral hypoxia and apnea.

Well it’s only 0.5-1% of children who die. Tell that to the parents. The best way to prevent this disease is vaccination, not just of the individual child but of all who come into contact with her. Herd immunity is the barrier between potentially fatal diseases and those who are too young to have received the vaccine and those whose immune system is compromised and the vaccine is not as effective.

Ok, that’s just one disease vaccinated against, the rest must be very safe. the vaccination schedule can help us here. The list of diseases vaccinated against and the complications for each is:

DiphtheriaThe bacterial toxin can lead to nerve paralysis and heart failure. Between 2—10 infected people in 100 die.
TetanusThe bacteria produce toxins which cause painful muscle    spasms and lockjaw. Hospital intensive care treatment is needed. About one in 10 patients dies. The risk is greatest for the very young or old.
Whooping CoughCovered above.
PolioAbout one in 20 hospitalised patients dies and 0.1—2 in 100 patients who survive is permanently paralysed. The overall risk of paralysis is about one in 100. This increases with age, ie, one in 75 adults. There are 2—10 fatalities in 100 cases from paralytic poliomyelitis. Post-polio syndrome may occur 30—40 years after poliomyelitis (ie, muscle pain and worsening of existing muscle weakness).
Hepatitis BThe virus causes liver infection and acute illness. Severe illness is rare in children. Fatalities are rare and are more likely in adults. Some people become carriers of the virus, especially children (six in 100). Liver cirrhosis occurs in one in 20 carriers (half of these will die). Liver cancer occurs in one in 10 male carriers and one in 20 female carriers and usually leads to death.
Haemophilus influenzae type bAbout one in 20 patients with meningitis dies and one in three survivors has permanent brain or nerve damage.About one in 100 patients with epiglottitis dies
PneumococcalAbout one in 10 children with pneumococcal meningitis die and one in six survivors will have permanent brain damage. About one in three children will be left with a hearing impairment after pneumococcal meningitis. Pneumonia and septicaemia (blood poisoning) leads to hospitalisation. Less severe illness, such as ear infections, may lead to deafness. Children with medical conditions such as congenital heart disease, some chronic lung diseases, kidney diseases, HIV infection, and children whose immune system is lowered through chemotherapy, radiation therapy, or organ transplant are at higher risk of pneumococcal disease. Children with spinal fluid shunts and with cochlear implants are also at higher risk of pneumococcal disease.
MeaslesCovered above.
MumpsIn about one in ten people it causes meningitis, but it is usually relatively mild. It causes encephalitis (inflammation of the brain) in about one in 6000 people, of whom one in 100 will die, and nerve deafness in one in 15,000 people. If infected after puberty, one in 5 males gets testicle inflammation and one in 20 females gets ovary inflammation. In rare cases this leads to infertility.
RubellaFor women in early pregnancy, 85% of babies infected during the first eight weeks after conception will have a major congenital abnormality such as deafness, blindness, brain damage, or a heart defect. This declines to about 10—20% by 16 weeks of the pregnancy. About one in 3000 patients gets thrombocytopaenia (low platelets causing bruising or bleeding). One in 6000 develops encephalitis (inflammation of the brain). This usually occurs in young adults. This may result in death.

Well, they all sound like a barrel of laughs, and perfectly safe. Seriously, the complications from these diseases are serious while the vaccines are relatively safe**.

That’s it for the IAS “philosophies”, while there are good recommendations mixed in (healthy diet, breast feeding) mostly it’s a collection of misinformation, misunderstanding and distortions. I am of two minds about this organisation as a whole, on the one hand I’m a proponent of free speech and that includes topics that I don’t agree with. On the other hand organisations like these have the potential to do great harm, both to individuals and greater society. Balancing these two things can be tricky and where to draw the line between them is not always clear.

On a related note, the Australian based anti-vaccination group the Australian Vaccination Network – has had it’s charitable status revoked. Part of this decision was based on the group’s failure to place a disclaimer on their website stating that it’s purpose was anti-vaccination and that it’s information should not be considered medical advice.

IAS also has charitable status. Under New Zealand law Charities must serve a charitable purpose, as specified by the Charities Act 2005:

Section 5(1) of the Charities Act 2005:
“In this Act, unless the context otherwise requires, charitable purpose includes every charitable purpose, whether it relates to the relief of poverty, the advancement of education or religion, or any other matter beneficial to the community.”

Given that the information distributed is often incorrect or presented in such a way as to misrepresent the facts I consider this organisation to fail both the “educational” and “beneficial” aspects of this definition. As such I would question the validity of it’s charitable status, but that’s for the law to decide not an irritable blogger***.

Finally, for accurate information on vaccines you should head on over to the Immunisation Advisory Centre, which also has a handy list of websites for both Parents and Health professionals.


*Although This can’t be far behind.

**No active intervention is 100% safe, no-one is claiming that.

***Similar to irritable bowel only more annoying.

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Filed under: Medicine, Psychological, Sciblogs, skepticism Tagged: DPT vaccine, health, Health and Medicine, Immune system, measles, mumps, New Zealand, Pertussis, Vaccination, Vaccine, Vaccine controversy

Randomness and Clustering: Is the Number of Twins in Timaru a Mystery? Darcy Cowan Aug 04


If you saw 3 News last night you might have caught the story about the bumper crop of twins born this year. The prologue to the story gave the impression of a mystery with words to the effect of  “Experts are at a loss to explain it”, I personally think this was a sloppy attempt to generate some “Experts are baffled” buzz around an essential pointless story that just filled up a slow news day.

Stuff also covered the story but without the mystery aspect, good thing because the stats given at the end of the piece kind of belie that approach.

“The previous year was another big year for twins with ten sets born out of 620 babies. In 2005 and 2006 there were 542 babies born, including six sets of twins. In 2004 and 2005 only two sets of twins were found among the 571 babies born and in the 2003 and 2004 year, there were sevens sets of twins and one set of triplets in the 557 babies born.”

So in other words the number goes up and down every year and this year just happened to be a cluster of births higher than average. Boring.

What’s the deal with randomness though and why are we so poor at recognising it? We tend to think of random events or locations as those that are approximately evenly distributed in time or space. This view of randomness however gives a false impression of what it means to be truly random.

Randomness is more a measure of unpredictability than it is of aesthetic impression. There are different ways of defining this property but one approach is to apply the criteria of an algorithm. An algorithm is essentially a series of instructions, the more instructions, the more complicated the algorithm. One such might be “1. from an initial number add 5, 2. repeat step 1.”. This would be an algorithmic representation of a sequence of numbers at regular increments of 5 eg 1,6,11,16,21.

Nothing random about that, the key here though would be that a sequence of really random numbers wouldn’t be able to be represented by an algorithm that was less complicated than the sequence itself, ie it would be it’s own algorithm and would not be able to be compressed any further.

What has this got to do with groups of twins? Well, if events such as the birth of twins are actually random (simplifying the world somewhat) then we would expect to see variations in the number of births in any one place. Based on this assumption we can look back at previous numbers to see whether this year is within the range we would expect.

Using the figures from the story and removing this year’s number and the year that only 2 twins were born as a possible outlier I get a range of between 0.5% and 2% of births being twins, with a high probability that normal variation will fall in this range. The percentage of twin births this year is 1.8%, high but apparently normal.

Now the sample size here is very small so I wouldn’t put too much trust in it but it is indicative that there is nothing really out of the ordinary going on here. According to the NZ Multiple Birth Association there were 900 multiple births last year in NZ (incl. triplets) this is about 1.4% of the 63,000 live births in NZ last year. So rough and ready these numbers may be but they aren’t too far off the mark, some places will be higher than average and others lower.

So when several rare(ish) events happen at the same time or place, consider; is this really unusual? What would we expect if it was just random?

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Filed under: Psychological, Sciblogs, Science, skepticism, Uncategorized Tagged: Multiple birth, New Zealand, Probability, randomness, Science

Smoking Bans and the Effect of Health Warnings Darcy Cowan Jan 21

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In the world today there is an increasing focus on the negative aspects of smoking and a concerted attempt to reduce the presence of smoking in society. Given the harmful effects of this addiction on not only the active smoker but those around them this seems like a prudent move. Two of the approaches with the goal of minimising public exposure to cigarette smoke are the banning of smoking in businesses and public places and the addition of more strenuous warning labels on the cigarettes themselves.

Both of these tactics have been used in New Zealand with varying levels of acceptance (and success). Smoking bans draw the criticism that individual freedoms are being curtailed. This may be a legitimate point but conceptually it is no different than government enforcement of wearing seatbelts while driving on public roads. The aim is to reduce the risk of harm to the public. The real question in each case is whether the intervention is effective in it’s goals.

Addressing this question two studies last year looked at each of these methods, the first I will look at is a meta-analysis (with the concomitant problems those have, that’s another story) of the effect of smoking bans on the hospital admissions of acute myocardial infarction (that’s a heart attack to you and me). The analysis found that smoking bans were associated with an average reduction of heart attacks by 17%.

For each year a ban was in place it was accompanied by a reduction of the incidence rate ratio (the number of new cases per unit of population eg 10 cases per 100,000 people) of 26%. This indicates that the longer a ban is in force the fewer people who will be affected by heart attacks. Looks like an effective strategy to me, 17% is nothing to be sneezed at when it is individual lives you are considering. Depending on individual risk factors the chance of death in the 30 days after a heart attack can be up to 16%.

An editorial discussing these findings in more depth (in the Journal of the American College of Cardiology, the journal this study was published in) can be found Here and is a good read.

The second study focused on the how well explicit (i.e. emphasising death) cigarette pack warnings encouraged smokers to quit. Specifically it looked at smokers for whom the act of smoking formed part of the basis for their self-esteem. Subjects undertook a questionnaire that evaluated whether smoking was tied to their self esteem using statements like ‘‘Smoking allows me to feel valued by others,’ and ‘‘Smoking allows me to feel worthy.’ (as well as negative versions). The subjects rated how much they agreed with the statements and this was used to determine the smoking-based self esteem for each subject.

Participants were then shown pictures of cigarette packs that either had mortality related warnings (e.g. ‘‘Smoking leads to deadly lung cancer.’) or more moral or self esteem related warnings (e.g. ‘‘Smoking brings you and the people around you severe damage’ and ‘‘Smoking makes you unattractive’). After a delay to allow the warnings to be filtered out of conscious awareness the subjects were asked a further series of questions to assess the effect of the warnings (e.g. ‘‘Do you intend to smoke more or less in the future?’ ‘‘Do you intend to quit smoking in the future?’).

Subjects for whom smoking formed part of the basis for their self esteem actually increased their likelihood of smoking in response to warnings emphasising mortality. For these people it was the self image warnings that were most effective. Unfortunately is seems that the opposite is true for individuals that do not consider smoking to be an important factor of their self esteem so a one size fits all approach would probably not be effective. The study authors suggest that specific populations could have warnings tailored to be most effective depending on the relevance smoking has to the group identity (e.g. “young smokers who want to impress their peers.”).

This result may be applicable to other areas where minimising harm is the goal, such as drink driving campaigns.

In summary, despite any reservations regarding the form that inducements to stop smoking take it seems that the benefits are indeed worth the attempt. Also, as I often point out, the real world is more nuanced and complicated than we would generally like it to be, more effort may be required to identify sub-groups that respond most to different strategies but this also looks to be worth trying.

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Posted in Medicine, Psychological, Sciblogs, Science Tagged: American College of Cardiology, Cigarette, health, Health and Medicine, Lung cancer, Myocardial infarction, New Zealand, Review, Science, Science and Society, smoking, Smoking ban, Tobacco smoking

Measles Outbreak Darcy Cowan Aug 07

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There was a story in the NZ Herald this week regarding a Measles outbreak in Auckland and the response to this event by the Powers That Be. Whether or not the action taken (keeping unvaccinated children at home following possible contact with carriers)  is correct, either practically or ethically is a question that will be endlessly discussed by others. I would like to focus on a point made in the article about vaccination coverage in New Zealand children. It was implied that approximately 25% of NZ children are unvaccinated, at the moment data is collected at childhood “milestones” 6,12,18 and 24 months of age. At 24 months the coverage is 77%, after this age no information (currently available) is collected but it is reasonable to expect that the numbers do not climb appreciably after this age.

I found it interesting that the article did not mention that compared with other developed countries this coverage is practically dismal. The coverage in the USA is >95%, though school attendance is predicated upon receiving vaccinations exemptions are available. In the UK where recently there have been concerns over vaccination rates dropping encouraging outbreaks over there, the coverage is still >80%. Even Australia has 82% coverage at age 5. The target coverage for NZ is >95%. Why do we lag behind?

According to the National Childhood Immunisation Survey conducted in 2005, 25% of those whose children do not receive the vaccinations have made this choice due to fears of vaccine safety (another 5% had concerns over a particular vaccine). 3% of respondents reported that they did not believe vaccines work at all. More mundane reasons were also quite prominent: child was on a different schedule or immunisation was done overseas – 19%, medical reasons – 11%, thought the child was vaccinated/not sure if vaccinated ~10%. A laundry list of other reasons each had <3%. Compared with the US where the reasons mostly cited were “Philosophical or Religious beliefs against vaccination” ~66%. Considering that in many states exemption due to religious reasons are about the only ones the law will accept (barring medical reasons) this is likely to cover a wider array of actual reasons.

How should NZ tackle the vaccination issue?

See also:

Evidence Based Thought: What’s wrong with catching the Measles?

Posted in Medicine, Psychological, Sciblogs, Science, skepticism Tagged: Children, epidemic, fears, measles, New Zealand, outbreak, survey, Vaccination

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