Decision making dyads and judgement overconfidence: Implications for high-risk industries.

In the workplace, overconfidence is generally considered undesirable as it may increase people's propensity to take risks. In many areas (e.g., aviation, shipping, nuclear control, and driving), risk-taking is detrimental to safety. We hypothesised that decision-makers would be overconfident and, due to group polarisation, decision-making pairs would be more overconfident than single decision-makers. As was predicted, when answering a 24-item general knowledge questionnaire (d = 0.94) and a task exploring how they might reorient themselves if lost (d = 1.93), participants (N = 63) were overconfident about their performance; importantly, participants in pairs (n = 32) were more overconfident on general knowledge (Hedges' g = 0.51) and lost procedures (Hedges' g = 0.52), than were participants who completed the tasks alone (n = 31). The findings imply that in some situations, single decision-makers may exhibit less overconfidence. The safety implications for a number of areas are discussed.

Debiasing visual pilots' weather-related decision making.

Pilots who decide to continue a flight into deteriorating weather conditions, rather than turn back or divert, are a significant cause of fatal crashes in general aviation. Earlier research has suggested that cognitive biases such as the anchoring effect and confirmation bias are implicated in many decisions to continue into worsening weather. In this study, we explored whether a simple debiasing technique, 'considering the alternative', reduced the effect of these two potentially fatal biases. Despite the study being adequately powered, our attempts to reduce the effects of biases were both unsuccessful. Negative findings such as these are particularly useful in aviation, as they can provide information on what does not work in this high stakes industry, even though such strategies may work elsewhere.

Operational efficiency of Asia-Pacific airports.

Airports are important drivers of economic development and thus under tremendous pressure from emerging competitors. However, few studies have analysed the operational efficiency of Asia-Pacific airports. This study therefore evaluated the operational efficiency of 21 Asia-Pacific airports between 2002 and 2011. A two-stage method was used: Data Envelopment Analysis (DEA) to assess airport efficiency, followed by the second-stage regression analysis to identify the key determinants of airport efficiency. The first-stage DEA results indicated that Adelaide, Beijing, Brisbane, Hong Kong, Melbourne, and Shenzhen are the efficient airports. The second-stage regression analysis suggested that percentage of international passengers handled by an airport, airport hinterland population size, dominant airline(s) of an airport when entering global airline strategic alliance, and an increase in GDP per capita are significant in explaining variations in airport efficiency.

Could mild hypoxia impair pilot decision making in emergencies?

The decreased pressure in the cabin of a pressurised aircraft (typically equivalent to ~8000 ft) reduces the oxygen level so that the blood oxygen saturation of all occupants falls from >97% (normoxia) at sea-level to below 92% (mild hypoxia). Although exposure to mild hypoxia does not affect well-learned cognitive and motor performance of aircrew, it has been proposed that it can affect the performance of some complex cognitive performance tasks involving multiple demands typical of emergency tasks that may have to be performed by pilots. In order to simulate some of these complex cognitive demands, 25 student volunteers participated in an experiment which assessed performance of complex logical reasoning and and multiple memory tasks before and after 2 hours of exposure to normoxia and mild hypoxia. Performance for the more difficult components of the complex reasoning task, especially involving conflict decisions, were marginally significantly degraded by mild hypoxia. Since the effects were only marginally significant future studies should investigate the effects of mild hypoxia on more subtle complex decision-making tasks.

Health benefits of deer and elk velvet antler supplements: a systematic review of randomised controlled studies.

AIMS: The aim of this systematic review was to evaluate the evidence from RCTs of velvet antler supplements for any condition, using the QUOROM statement as a guiding framework. METHODS: Four electronic databases (PubMed, Medline, Web of Science and Academic search premier, via the bibliographical platform, Endnote) and two review articles were searched for all randomised clinical trials of velvet antler supplements. Retrieved trials were evaluated according to standardised criteria. RESULTS: Seven RCTs were identified as satisfying all inclusion criteria and examined the effectiveness of velvet antler for rheumatoid arthritis (2), osteoarthritis (1), sexual function (1), and sporting performance enhancement (3). Their methodological quality ranged from 3-5, as measured on the Jadad scale. Two RCTs reported some positive effects of velvet antler supplements, but neither were convincing while the remaining five RCTs found no effect of velvet antler supplements. CONCLUSIONS: Claims made for velvet antler supplements do not appear to be based upon rigorous research from human trials, although for osteoarthritis the findings may have some promise.

Chiropractic claims in the English-speaking world.

BACKGROUND: Some chiropractors and their associations claim that chiropractic is effective for conditions that lack sound supporting evidence or scientific rationale. This study therefore sought to determine the frequency of World Wide Web claims of chiropractors and their associations to treat, asthma, headache/migraine, infant colic, colic, ear infection/earache/otitis media, neck pain, whiplash (not supported by sound evidence), and lower back pain (supported by some evidence). METHODS: A review of 200 chiropractor websites and 9 chiropractic associations' World Wide Web claims in Australia, Canada, New Zealand, the United Kingdom, and the United States was conducted between 1 October 2008 and 26 November 2008. The outcome measure was claims (either direct or indirect) regarding the eight reviewed conditions, made in the context of chiropractic treatment. RESULTS: We found evidence that 190 (95%) chiropractor websites made unsubstantiated claims regarding at least one of the conditions. When colic and infant colic data were collapsed into one heading, there was evidence that 76 (38%) chiropractor websites made unsubstantiated claims about all the conditions not supported by sound evidence. Fifty-six (28%) websites and 4 of the 9 (44%) associations made claims about lower back pain, whereas 179 (90%) websites and all 9 associations made unsubstantiated claims about headache/migraine. Unsubstantiated claims were made about asthma, ear infection/earache/otitis media, neck pain, CONCLUSIONS: The majority of chiropractors and their associations in the English-speaking world seem to make therapeutic claims that are not supported by sound evidence, whilst only 28% of chiropractor websites promote lower back pain, which is supported by some evidence. We suggest the ubiquity of the unsubstantiated claims constitutes an ethical and public health issue.