Just occasionally someone asks if everything we believe about causation-related science is wrong. This time, the use of the t-test is a cause of doubt. In the interpretation of rat lab results, animal experimenters use the t-test. The t-test, when used as originally designed, compares the means of two data distributions. The standard deviation of the distribution is first reduced to the standard error of the mean (SEM) and compared with the mean and SEM of the other distribution. If p < 0.05 it is pronounced that the two distributions are probably different. So, when comparing control animals with those dosed with a toxin the t-test is used to detect the likelihood that the toxin did anything. The reason for doubt is that SEM comparisons are only valid for true means. The single result e.g. 4 out of 90 rats developed lung cancer, is not a mean. Despite this, experimental scientists use the t-test to decide if 4/90 is different from 5/90. In fact the same experiment, when repeated, h
This study has many high quality characteristics including high participation rates, prospective design, and objective data on TBI and dementia and a several medical confounders. It can be found here: Jesse R Fann et al. Lancet Psychiatry http://dx.doi.org/10.1016/S2215-0366(18)30065-8. The study includes 126,734 dementia cases in the analysis; 6,374 had experienced TBI. A potentially powerful study. The data clearly shows an increased risk of dementia diagnosis within the 2 years following TBI. However, there is no variation in risk between 4 and 14 years after TBI, suggesting a completely uniform acceleration, which would be hard to explain. There is also decreasing risk as age increases, yet older people are more vulnerable to dementia. This also is hard to explain. The authors call for more to be done to prevent TBI. Dementia is a growing problem. Motor and sports insurers would be especially sensitive to this issue if it turned out that TBI was a legal cause of dementia. Especiall
Liability ENID modelling has recently been added to our standard Radar service. (ENID = Event not in Data). What it is. For a given ENID scenario, the new modelling creates an annual liability loss distribution curve for a given jurisdiction e.g. UK. It then apportions the mean loss across industry codes. Where relevant, the time development of that loss is also estimated from latency periods and from likely dates of knowledge. The time-is-money value of reserving for the loss can then be estimated and the potential opportunity cost of delayed reserving can be calculated. Given that emerging risks arise from science studies it should be no surprise that the same studies can be analysed to give estimates of attributable frequency of loss. Other work is then used to assess how many of these attributable losses could make a reasonable liability claim. For example, if half the attributable cases could prove a breach of duty then the attributable frequency is at most, half the attributable
A new publication describes the role of risk management in commercial nanotechnology projects. Risk appetite is the unifying concept. It follows that risk transfer is an essential component when there is uncertainty. The paper identifies commonly available measurements which scale with risk, are (to a large extent) mutually orthogonal with respect to risk, are generalisable across reasonably clear hazard groupings, remain valid when combined into a risk value and can be calibrated against research findings and commercial feedback. The limited set of these will not serve the highly sophisticated precautionary regulatory purpose. Quantitative nano-specific injury risk evaluation for regulatory purposes is still a long way off. In the mean time, risk generators and liability insurers may benefit from a shared approach to nano risks. Such an approach would support the development of expertise. The paper can be read free of charge until 28th May 2017. Included is a link to a free, confident
Prudential regulation of insurance has been transferred to a new unit at the Bank of England – the Prudential Regulation Authority (PRA). The PRA’s approach to regulation and supervision has three characteristics: A judgement-based approach: The PRA will use judgement in determining whether financial firms are safe and sound, whether insurers provide appropriate protection for policyholders and whether firms continue to meet the Threshold Conditions. A forward-looking approach: The PRA will assess firms not just against current risks, but also against those that could plausibly arise in the future. Where the PRA judges it necessary to intervene, it will generally aim to do so at an early stage. A focused approach: The PRA will focus on those issues and those firms that pose the greatest risk to the stability of the UK financial system and policyholders. The PRA approach to supervision will not seek to operate a “zero-failure” regime. Rather, the PRA will seek to ensure that a f
Evidence from: “Call for Participants IST-2006 Workshop on Affective Computing” 31st Aug 2006 BfR news release “Indications that styrene has a tumorigenic effect in humans” TR Fennell et al. Toxicological Sciences (2006) Vol. 93(2) p 256-267 “Kinetics of Elimination of Urinary Metabolites of Acrylamide in Humans” YM Hung et al. Am. J. Emergency Med. (2006) Vol.24 p 714 – 716 “Weight-reducing regimen associated with polymorphic ventricular tachycardia” MC Michalski et al. Trends in Food Science & Technology 17 (2006) 423–437 “Does homogenization affect the human health properties of cow’s milk?” A Elder et al. Environ Health Persp. (2006) Vol. 114 p 1172 – 1178 “Translocation of Inhaled Ultrafine Manganese Oxide Particles to the Central Nervous System” Further detail: 6#7-8 35 BB
Dysregulation of blood glucose is linked to a large number of serious disorders including heart disease. This study reports a link between shift work and elevated blood glucose levels [possibly a sign of diabetes]. Further work is needed to establish whether this is the norm or just a result of the timing of the testing work. Evidence from: Y Suwazono et al. J Occ Env Med (2006) Vol.48 p 455 – 461. “Long-Term Longitudinal Study on the Relationship Between Alternating Shift Work and the Onset of Diabetes Mellitus in Male Japanese Workers” A mechanism for harm adds weight to causation arguments. Further detail: 6#3-4 24
Evidence from: “Recycling” Increased commercial recycling activity is anticipated. For example the Waste Electrical and Electronic Equipment Regulations [currently in draft form; due to come into force on 1/1/2007] will increase the volume of collection, dismantling and disposal work. Hazards include manual handling, implosion (CRT screens), toxic metals, and PCBs. Comment Thus far, much of the exposure to toxins in the recycling and disposal of electronic goods has been exported to third world countries.
Evidence from: Environment Agency Press Release June 2006. “Homeowners warned over domestic oil tank usage” The Environment Agency report that oil from domestic sources is the most frequently identified source of oil pollution. There are an estimated 1 million domestic storage tanks in use but many do not have a bunding system in place (bunding is now usually integral to the storage tank). The press release states that some insurance policies will only pay out when oil damages the house or any adjacent property. When a spill is contained within the garden, the homeowner is left to foot the clean-up bill. Fines are applicable to situations where oil contaminates drinking water supplies (limit £20,000); leaving an oil spill to self remediate may not be a sensible option. The report continues: “It would only take one litre of oil to contaminate one million litres of drinking water if it entered a water source and so the Environment Agency is urging homeowners to be more
Evidence from: SK Mathiassen et al. J Agric Food Chem (2006) Vol.54 p 1058 – 1063 “Herbicidal Effects of Soil-Incorporated Wheat” The authors noted that wheat plants contain several chemicals with weak weed killing properties. In field trials, when wheat plants were ploughed-in after harvest, a small effect was noted on the numbers of weeds germinating and their growth in next years crops. With genetic modification, crop plants could be made to continuously exude these chemicals or to increase the dose when ploughed-in. Comment Control of such modification would need to be exceptionally reliable.
Evidence from: HSL and HSE “Psychosocial Working Conditions in Great Britain in 2005” The report examined changes in the levels of the six chosen stressors and related these to self-reported stress levels. There was a link between relationship quality and stress levels but no consistent trend. there was no relevance from role clarity and changes at work. The work would support argument based on a proposed lack of relevance of the stress management standards. This could count in favour of Defendants or Claimants, depending on the circumstances of the case. Further detail: 6#1 38
Intentionally added ingredients may contain allergens. The plan is to ensure that these are included on label. A precautionary response is anticipated, devaluing the meaning of the label. It is not easy to see how an overcautious label would create new liabilities. Product liability is strict. Contract liability issues can be anticipated where composition information from suppliers and quality assurance services proves to be inaccurate. Evidence from: Directive 2000/13/EC OJ L 109, 6.5.2000 On the 6th September 2001 the Commission issued a proposal for an amendment to the food labelling Directive (Directive 2000/13/EC OJ L 109, 6.5.2000). The proposal will abolish the “25% rule” which currently means that it is not obligatory to label the components of compound ingredients that make up less than 25% of the final food product. The new proposal means that all ingredients intentionally added will have to be included on the label. The proposal will also establish a list of ingr
HSE has been vigorously promoting interventions where workplace causation is in doubt. This choice may cause HSE some difficulty meetings its agreed targets. One solution would be to accept that causation was rather too easily being assigned. Evidence from: D Coggon. Occupational and Environmental Medicine. November (2001) Vol.58 # 11 p 691. HSE activity on occupational health has been challenged by the setting of targets to be met within 5 and 10 years (from 2000). However, the actual targets and baselines have caused considerable debate. This paper brings some of the more scientific arguments into the open, they illustrate the difficulties HSE have in deciding what an occupational disease is. Revitalising H&S set targets: “a 20% reduction in the incidence of work related ill health to be achieved by the year 2010”. Considerable doubt remains about the definition and measurement of current levels and what proportion of these really can be eliminated by better practice. [Andrew Aut
Epidemiology provides data and tools with which to measure case load and to estimate liability exposure. Key concept = attributable risk; the basis of reliable probabilistic estimates of exposure. Evidence from: Andrew@reliabilityoxford.co.uk Attributable Risk If an exposure to a risk leads to an increased rate of ill health outcome, the absolute effect of exposure is measured by the difference between rate of occurrence in the exposed group (RE) and the rate occurrence in the unexposed group (RU). The difference in these rates, measures the rate attributable to exposure to the risk. Attributable risk rate = RE – RU Following from this; Attributable Fraction = (RE – RU )/ RU Which is the same as; Attributable Fraction = (RR-1)/RR where RR = relative risk, the result obtained from most epidemiological studies). For example, a RR of 2 gives an attributable fraction of 50%. For example, a RR of 3 gives an attributable fraction of 66%. It is quite possible for an individual to
The study examined the outcomes of lumbar fusion surgery in Worker’s Compensation supported patients. Evidence from: MScott et al. Spine. April (2001) Vol. 26 #7 p 738 Improved quality of life was detectable in half of cases that had the surgery. Litigation was a strong but imprecise predictor of post-operative disability. The Radar report is available to subscribers: 1#4 7
Evidence from: Thorax. April (2001) Vol.56 #4 p.251. A statement made by the British Thoracic Society covering diagnosis, cause and treatment for mesothelioma. The briefest highlights are reported here. Causation: • 1 in 10,000 cases are truly spontaneous. • Erionite also causes it. • Simian (SV(40)) virus has been proposed but not strongly supported. • Most cases are caused by asbestos. • In subjects heavily exposed to asbestos early in life more than 10% may die of mesothelioma. Relative Risk: Blue and brown asbestos are the most potent. Levels in well-maintained buildings are a small risk. Latency: From first exposure, to death has a mean of 41 years, rarely less than 15 years. Prognosis: Survival 8 – 14 months from diagnosis. Diagnosis: Occupational history is a key factor in diagnosis. The statement also includes advice on making an insurance claim for pleural mesothelioma! Comment Many of these views are well supported by published evidence.
Evidence from: Andrew@reliabilityoxford.co.uk Risk Ratios are usually accompanied by an estimate of precision measured by the 95% confidence interval (CI). What this means is that the true risk ratio (for that particular study) has a 95% probability of falling within the stated range and that its most likely value is the one reported. For example, a RR of 2.1 (95% CI 1.8 to 3.1) means that the ‘true’ risk ratio has a 95% probability of being between 1.8 and 3.1, the most likely value being 2.1. The wider the 95% CI the less probable the stated RR. If the 95% CI includes 1.0 the result is usually considered not to be statistically valid. E.g. RR = 2.1 (95% CI = 0.8 to 5.6) and e.g. RR = 0.75 (95% CI = 0.4 to 1.5). It is debatable whether or not the 95% confidence interval is the appropriate one to consider in the context of the civil law. The usual test of evidence at civil law is that of the balance of probabilities, or >50%. It is technically possible to quote the results of epidem
This academic research investigated a proposed link between manifest allergy and death from cardiovascular disease. Allergy status was prospectively determined using a battery of skin-prick tests. Evidence from: PJ Gergen et al. Clinical and Experimental Allergy December (2000) Vol. 30 p.1717. If allergy was a risk factor for fatal disease then those which should be controlled e.g. occupational allergens, could give rise to liabilities. Data from research such as this could provide a prospective estimate of the case load. The Radar report is available to subscribers: 1#2 8
The speech by Peter Skinner MEP highlights sun light, stress and ergonomics as the key focus of regulatory attention in the coming years. Evidence from: Conference report, Bilbao 27th November 2000. Peter Skinner was particularly encouraged by the emergence of ergonomics standards in the USA. These are reported elsewhere in this database. The Radar report is available to subscribers: 1#1 12