Ken Perrott

Dr Ken Perrott trained as a chemist and his research background is in surface chemistry, soil science and fertiliser chemistry. After working in the DSIR (Chemistry Division and Soil Bureau), MAF, MAFTech and AgResearch he is now retired. Ken enjoys discussion of the wider social and philosophical issue surrounding science. Unfortunately these issues are often misrepresented in our society and he believe scientists have a responsibility to counter unscientific thinking and movements. This is one of the reasons Ken got into blogging, starting up Open Parachute in the middle of 2007.

Yet another fluoride-IQ study - Open Parachute

Jan 31, 2018

As with most of these fluoride-IQ studies this one is only relevant to areas of endemic fluorosis (This is from a UNESCO paper and has been corrected for New Zealand. Identification of fluorosis in a country does not imply the whole country is high fluoride). Yes, it’s a bit like groundhog day. Another fluoride-IQ study – and we expect this to be followed by another round of claims by anti-fluoride propagandists that this is the death knell to community water fluoridation. That this study provides the “irrefutable proof” that fluoride is a “neurotoxin.” But that interpretation is completely wrong. This new study does nothing of the sort – in fact, quite the opposite. The new study is: Duan, Q., Jiao, J., Chen, X., & Wang, X. (2017). Association between water fluoride and the level of children’s intelligence: a dose-response meta-analysis.  … Read More

Confirmation bias – we all suffer from it but how can we reduce its effect? - Open Parachute

Jan 10, 2018

Confirmation bias – we all suffer from it. It’s just part of being human. According to Psychology Today, Confirmation bias occurs from the direct influence of desire on beliefs. When people would like a certain idea/concept to be true, they end up believing it to be true. They are motivated by wishful thinking. This error leads the individual to stop gathering information when the evidence gathered so far confirms the views (prejudices) one would like to be true. Sure, we are capable of rational thought but it is often overridden by our emotional messages. And even in the best situations, our attempt at rational thought is inevitably contaminated by our emotions. This video from Above the Noise • PBS explains what is going on in a popular way. It even resorts to brain scans! Word of warning, though. It inevitably suffers … Read More

Anti-fluoridationists misrepresent New Zealand dental data – an annual event - Open Parachute

Dec 18, 2017

  Caught again! – NZ anti-fluoride campaigners tell their annual porky about the MoH statistics for the dental health of school children. This exercise in confirmation bias by New Zealand anti-fluoridation campaigners has become an annual tradition involving confirmation bias and cherry-picking. Every year the Ministry of Health (MoH) releases a spreadsheet containing the most recent data on school children’s dental health. And every year the Fluoride Free NZ (FFNZ) activists select some figures from the spreadsheet to argue their case that fluoridation is not effective. A simple exercise in bias confirmation by cherry picking. I wrote about last year’s exercise in my article Anti-fluoridationists misrepresent new dental data for New Zealand children. That involved the MoH data for 2015. My comments on their misrepresentation of the newly released 2016 data will be much the same. FFNZ claims the 2016 statistics: “show absolutely … Read More

Fluoridation means money in the pocket - Open Parachute

Dec 07, 2017

The ordinary person – not the taxation-financed health system – is the main financial beneficiary of community water fluoridation, according to a new study from New Zealand researchers. Their research confirmed that community water fluoridation in New Zealand is highly cost-effective for all but the smallest communities. This study updates previous evaluations by including data for adults – previous studies were limited to children. It also corrected for under-estimation of averted dental restoration costs in a previous study. The authors also make the point that an update is necessary because: “Sound public health practice requires periodic re-evaluation of interventions’ benefits and costs.” The results are reported in the paper: Moore, D., Poynton, M., Broadbent, J. M., & Thomson, W. M. (2017). The costs and benefits of water fluoridation in NZ. BMC Oral Health, 17(1), 134. Community size As with previous studies, the results … Read More

Anti-fluoridation campaigners often use statistical significance to confirm bias - Open Parachute

Dec 06, 2017

Frankly, these days I just get turned off by media reports of studies showing statistically significant relationships as evidence for or against the latest health or other fads. I was pleased to read this Nature article – Five ways to fix statistics – recently as it mirrors my concern at the way statistical analysis is sometimes used to justify or confirm a bias and not reveal a real causal relationship.   As the Nature article says, statistical significance tests often amount “to uncertainty laundering:” “Any study, no matter how poorly designed and conducted, can lead to statistical significance and thus a declaration of truth or falsity. NHST [null hypothesis significance testing] was supposed to protect researchers from over-interpreting noisy data. Now it has the opposite effect.” No matter how good a relationship appears, or how significant the statistical analysis shows it to … Read More

NZ blogs sitemeter rankings – November ’17 - Open Parachute

Dec 01, 2017

 Here are the rankings of New Zealand blogs with publicly available statistics for November 2017.  Of course, Statcounter has decided to change their format again and this has caused another headache this month. Every time this happens it screws up the existing methods for automatically downloading the statistics. I notice a few regulars no longer allow public access to the site counters. This may happen accidentally if the format of the blog is altered. If your blog is unexpectedly missing please check this out. Send me the URL for your site meter and I can correct the information in the database. Sitemeter is no longer working so the total number of NZ blogs in this list has been drastically reduced. I recommend anyone with Sitemeter consider transferring to one of the other meters. See   … Read More

The problem with scepticism - Open Parachute

Nov 30, 2017

Being a sceptic has its problems. On the one hand, a sceptical approach to information has never been more necessary. On the other hand labelling oneself a Sceptic (or Skeptic) can have negative results – encouraging arrogance and inability to accept criticism. I have been thinking about this a lot lately and have again and again found myself encouraging a sceptical approach to everything we read – from whatever source. But I also found myself largely agreeing with a recent article in Patheos critical of sceptics by Matthew Facciani – Why Identifying As A Skeptic Can Be Problematic.  Then I attended (partially) the NZ Skeptics conference in Wellington last weekend – a great conference with some excellent presentations. But something that struck me during the conference is that the scepticism was really limited to what Wikipedia defines as scientific  or … Read More

Is synthetic meat ethical? - Open Parachute

Nov 30, 2017

I am deeply ashamed of it now – but at the time it seemed like an experience I couldn’t afford to miss. It was so exotic – and I was travelling. Twenty years ago I ate at a restaurant in Johannesburg, the Republic of South Africa,  which specialised in meat dishes – from game animals. It was a real feast. Stews of ostrich, zebra, hippo, giraffe and other animal meats. Not something us New Zealanders normally experience. But I no longer eat animal meats – and haven’t for several years. My decision is based on ethical considerations. So you can understand my shame. Some might call me a weirdo – but I do not think my ethical decision is really all that unusual. Vegetarianism, veganism and similar dietary approaches are relatively common these days. And I think there are many more of us … Read More

Anti-fluoride “expert” finds the real reason oral health has improved – and it’s not fluoride - Open Parachute

Nov 15, 2017

 Anti-fluoride campaigners always promote people like Geoff Pain as “renowned” or “world experts.” They aren’t. Pain has no credible scientific publications on fluoride. No, in fact, he claims lead is responsible for tooth decay and the improvement in oral health is a result of removing airborne lead contamination. And the “proof” is even in the title of his report – “Global Decline in Tooth Decay correlates with reduced Airborne Lead (Pb) but water Fluoridation prevents further progress“ Mind you, the word “correlate” appears only twice in the document – once in the title and once in the abstract. Nowhere else. Scientists usually restrict the use of words like this to results of proper statistical analyses – but he presents no evidence of a correlation anywhere in the document. OK, we shouldn’t expect any better. This document is just another … Read More

October ’17 – NZ blogs sitemeter ranking - Open Parachute

Nov 02, 2017

Here are the rankings of New Zealand blogs with publicly available statistics for October 2017. Of course, Statcounter has decided to change their format and this has caused a headache this month. Every time this happens it screws up the existing methods for automatically downloading the statistics. I notice a few regulars no longer allow public access to the site counters. This may happen accidentally if the format of the blog is altered. If your blog is unexpectedly missing please check this out. Send me the URL for your site meter and I can correct the information in the database. Sitemeter is no longer working so the total number of NZ blogs in this list has been drastically reduced. I recommend anyone with Sitemeter consider transferring to one of the other meters. See   … Read More