Avoiding bias in medical research

Most people are rather vague when reporting on food and drink consumption, smoking and exercise habits. General practitioners, however, are skilled at interpreting phrases such as “I only have a few drinks rarely…each week” and “I get to the gym regularly” and can estimate based on symptoms and a person’s physical appearance just how precise those claims are. However, it is crucial for healthcare research and epidemiology that relies on patient self-reporting that we find a more objective, rather than intuitive, way to identify bias in self-reporting.

A new statistical approach to address the problem of bias in self-reporting has been developed by a team at Washington State University in Pullman. The technique, reported in a forthcoming issue of the International Journal of Behavioural and Healthcare Research, is based on stochastic frontier estimation (SFE). SFE is more commonly used in economics and market research to spot statistical errors and unanticipated deviations from the norms in data. The approach helps highlight when the subjects of medical research may either deliberately or inadvertently bias the information they provide to researchers.

“There are many reasons individuals might offer biased estimates of self-assessed behavior, ranging from a misunderstanding of what a proper measurement is to social-desirability bias, where the respondent wants to ‘look good’ in the survey, even if the survey is anonymous,” explains Robert Rosenman, , who coauthored the study with Laura Hill and Vidhura Tennekoon. “Response bias itself can be problematic in program evaluation and research, but is especially troublesome when it causes a recalibration of bias after an intervention,” he adds.

SFE can identify bias at specific times in self-reported data and in particular identify bias after a healthcare intervention so that researchers can determine whether or not self-reporting patients have biased their responses because they presume the intervention should have caused changes. This characteristic of the technique could ensure that double-blind placebo-controlled trials are more robust in terms of the validity of data. It could help improve results obtained before and after an experimental treatment is given to one group and the placebo to another when neither party, patient or researcher, is aware in advance of which group a patient is in.

Using data involving family dynamics and interventions to help strengthen family bonds, the team has demonstrated the statistical aspects of the SFE approach. “SFE allows the researcher to identify bias and causal factors at the individual level, it expands our ability to identify, understand, explain, and potentially correct for, response shift bias,” Rosenman explains.

“Measuring bias in self-reported data” in Int. J. Behavioural and Healthcare Research, 2011, 2, 320-332

Infecting hospital staff with contagious awareness

Infections picked up in hospital affect almost a third of patients in intensive care, and kill 44% of those people. Given that some infectious agents can linger for weeks or months it is increasingly important that staff awareness of the problem is improved and that training in infection prevention across the National Health Service and in private healthcare is expanded, according to researchers at the University of Northampton.

Microbes such as methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile (C. difficile), glycopeptide resistant enterococci (GRE), vancomycin-resistant enterococci (VRE) and Streptococcus spp. (e.g. alpha-haemolytic) are the biggest infection threats to patients under NHS care. Now, writing in the International Journal of Behavioural and Healthcare Research, Terry Tudor, a researcher in Waste Management within the University’s Centre for Sustainable Waste Management points out that training in infection prevention and in the control of waste in hospitals is critical to reducing infection rates caused by these and other pathogens. Bacteria, viruses and other pathogens are generally spread through direct contact with contaminated surfaces or staff or through the air in the case of airborne organisms.

Tudor points out that the prevalence of MRSA and C. difficile has fallen recently within the NHS, although whether this is due to improved hygiene and deep-cleaning procedures or other factors is not yet known. “The management of various factors in the physical environment, including clinical waste has been demonstrated to impact upon levels of pathogens,” he explains. However, there are social and economic factors to consider if further improvements are to be made. Staff perceptions have to be addressed through training at all levels in order to sustain improvements that have been made and to avoid complacency creeping in. Importantly, there have to be efforts to consider the associated environmental impact and cost of managing hazardous medical waste, says Tudor.

Infection is not only about hygiene it is about attitude from management through to ward staff. “Differences in practices by different job categories suggest that any initiatives should be targeted towards specific job categories and have the support of senior managers if they are to be successful. In addition, there should be particular attention paid to younger staff who have been employed for less than ten years at the site,” he concludes.

“Overcoming attitudes and perceptions towards the management of infections and waste in the hospital setting: a case study from the UK” in International Journal of Behavioural and Healthcare Research, 2011, 2, 307-319

Protect and reward on the Internet

With a third of the world’s population now on the internet and billions of devices interconnected via myriad wireless and wired networks, the risks of so-called cyber attacks are more apparent than ever. Espionage, denial-of-service, malware and so-called cyber war and terrorism represent significant risks to individuals, corporations, institutions and governments at various levels.

Writing in the International Journal of Management and Decision Making, researchers in Germany have proposed a novel approach to network protection that could reduce the risk of cyber attack by rewarding those organisations that bolster the security on their networks to prevent the spread of malware and other problems. Because internet and computer-based systems today communicate more and more with one another, mostly as anonymous partners, they are becoming increasingly vulnerable to cyber harassment and cyber attacks, the researchers explain.

Annette Hofmann of the University of Hamburg and Hidajet Ramaj of the Humboldt-Universitaet zu Berlin explain that international or national agreements could be used to build coordinative reward systems and to subsidise high-exposure organisations. Improving network security on vulnerable sites and systems would, they suggest, hinder the rapid spread of malicious software that is commonly used to create bot-nets for attacking corporate and other networks. Because internet and computer-based systems today communicate more and more with one another, mostly as anonymous partners, they are becoming increasingly vulnerable to cyber attacks.

The researchers explain that currently, only some parties invest in protection against cyber attack, which adds to their costs, but benefits them in terms of their own protection and has some benefit to the entire community. With a reward system in place everyone from small-town travel agents to multinational credit card companies could become involved with a scaled reward system that reduces those overhead proportionately and benefits the community as a whole to a much greater extent by motivating them all to ensure that their systems are secure.

The team adds that, formal contractual agreements between different parties that specify their data and information exchange and other interactions would also have to be implemented to reduce inefficiency and improve network protection. “Such agreements may serve to commit the parties to their cyber risk protection strategy,” the team concludes.

“Interdependent risk networks: the threat of cyber attack” in Int. J. Management and Decision Making, 2011, 11, 312-323