The development of a tool to predict team performance.

The paper describes the development of a tool to predict quantitatively the success of a team when executing a process. The tool was developed for the UK defence industry, though it may be useful in other domains. It is expected to be used by systems engineers in initial stages of systems design, when concepts are still fluid, including the structure of the team(s) which are expected to be operators within the system. It enables answers to be calculated for questions such as "What happens if I reduce team size?" and "Can I reduce the qualifications necessary to execute this process and still achieve the required level of success?". The tool has undergone verification and validation; it predicts fairly well and shows promise. An unexpected finding is that the tool creates a good a priori argument for significant attention to Human Factors Integration in systems projects. The simulations show that if a systems project takes full account of human factors integration (selection, training, process design, interaction design, culture, etc.) then the likelihood of team success will be in excess of 0.95. As the project derogates from this state, the likelihood of team success will drop as low as 0.05. If the team has good internal communications and good individuals in key roles, the likelihood of success rises towards 0.25. Even with a team comprising the best individuals, p(success) will not be greater than 0.35. It is hoped that these results will be useful for human factors professionals involved in systems design.

Writing a Cochrane systematic review on preventive interventions to improve safety: the case of the construction industry.

OBJECTIVES: The objective of this paper is to describe the main steps and to conduct a systematic literature review on preventive interventions concerning work-related injuries and to illustrate the process. METHODS: Based on the Cochrane handbook, a structured framework of six steps was outlined for the development of a systematic review. This framework was used to describe a Cochrane systematic review (CSR) on the effectiveness of interventions to prevent work related injuries in the construction industry. RESULTS: The 6 main steps to write a CSR were: formulating the problem and objectives; locating and selecting studies; assessing study quality; collecting data; analysing data and presenting results; and interpreting results. The CSR on preventing injuries in the construction industry yielded five eligible intervention studies. Re-analysis of original injury data of the studies on regulatory interventions, through correcting for pre-intervention injury trends led to different conclusions about the effectiveness of interventions than those reported in the original studies. CONCLUSIONS: The Cochrane handbook for systematic reviews of interventions provides a practical and feasible six-step framework for developing and reporting a systematic review for preventive interventions.

The influence of rifle carriage on the kinetics of human gait.

The influence that rifle carriage has on human gait has received little attention in the published literature. Rifle carriage has two main effects, to add load to the anterior of the body and to restrict natural arm swing patterns. Kinetic data were collected from 15 male participants, with 10 trials in each of four experimental conditions. The conditions were: walking without a load (used as a control condition); carrying a lightweight rifle simulator, which restricted arm movements but applied no additional load; wearing a 4.4 kg diving belt, which allowed arms to move freely; carrying a weighted (4.4 kg) replica SA80 rifle. Walking speed was fixed at 1.5 m/s (+/-5%) and data were sampled at 400 Hz. Results showed that rifle carriage significantly alters the ground reaction forces produced during walking, the most important effects being an increase in the impact peak and mediolateral forces. This study suggests that these effects are due to the increased range of motion of the body's centre of mass caused by the impeding of natural arm swing patterns. The subsequent effect on the potential development of injuries in rifle carriers is unknown.

Initial force and postural adaptations when pushing and pulling on floor surfaces with good and reduced resistance to slipping.

The objective of the present study was to determine whether differences in the frictional properties of a floor surface may affect the kinematics and kinetics of pushing and pulling. Eight male participants were required to push and pull a four-wheeled trolley over two level surfaces, on which were mounted floor coverings with good (safety floor) and reduced (standard floor) frictional properties. A psychophysical approach was used to determine the initial maximum acceptable horizontal force required to move the trolley over a short distance (3 m). Three-dimensional (3D) hand and ground reaction forces and 3D postures were measured during initial force exertions. The results showed that psychophysically derived measures of initial horizontal force and horizontal components of hand forces did not differ significantly between floor surfaces. Despite the ability to exert similar forces, the measured maximum coefficient of friction varied according to floor surface. These changes reflected significant alterations in vertical and horizontal components of ground reaction and vertical hand forces, suggesting that participants had maximized the frictional properties available to them. Postures also changed as a consequence of floor surface, with significant changes occurring in knee flexion and trunk extension. This study has shown that handlers involved in the pushing and pulling of trolleys are capable of adjusting posture and the direction of hand and foot forces in order to compensate for reduced levels of floor friction. This has particular relevance when assessing the musculoskeletal loads imposed on the handler and the likely mechanisms of injury resulting from variations in floor conditions when workers undertake pushing and pulling tasks in the workplace.

Anxiety and depression in the workplace: effects on the individual and organisation (a focus group investigation).

BACKGROUND: While the prevalence of anxiety and depression has increased, little is known of the impact on working life. The aim of this study was to explore the effects of anxiety and depression and the treatment for these conditions on performance and safety in the workplace. METHOD: Nine focus groups were conducted with employees who had suffered anxiety and depression. A further 3 groups comprised staff from human resources and occupational health. The sample comprised 74 individuals aged 18-60 years, from a range of occupations. Results were presented to a panel of experts to consider the clinical implications. RESULTS: Workers reported that the symptoms and medication impaired work performance, describing accidents which they attributed to their condition/medication. Respondents were largely unprepared for the fact that the medication might make them feel worse initially. Employees were reluctant to disclose their condition to colleagues due to the stigma attached to mental illness. LIMITATIONS: People who had experienced problems with managing their symptoms and medication at work are more likely to volunteer to participate in such a study than those who had a satisfactory experience. Also, the researchers had no background information on severity of mental health problems of participants. CONCLUSIONS: Anxiety and depression were associated with impaired work performance and safety. The authors consider the implications for health care and the management of mental health problems at work.

Perceptions of the impact of depression and anxiety and the medication for these conditions on safety in the workplace.

BACKGROUND: The number of people taking prescribed medication for anxiety and depression has increased greatly, but little is known of how this medication impacts on safety at work. AIMS: To examine the relation between anxiety and depression, prescribed medication, performance, and safety in the workplace. METHODS: The research involved nine focus groups with sufferers of anxiety and depression to investigate experiences of mental health problems and the impact of psychotropic drugs. A further three focus groups were conducted with staff in human resources, personnel, occupational health, and health and safety departments, to explore organisational perspectives. The sample comprised 74 individuals drawn from a wide range of occupational sectors. Finally, the results were presented to a panel of experts from occupational medicine, general practice, psychology, health and safety, and psychiatry, to consider the implications for practice. RESULTS: Workers reported that both the symptoms and the medication impaired work performance. Participants described accidents which they attributed to their condition or to the medication. Workers with responsibilities for others, such as teachers, healthcare workers, and managers appeared to present a particular safety risk. Healthcare workers believed that they placed themselves and their patients at risk when carrying out medical procedures. CONCLUSIONS: Respondents in this study felt that their symptoms of anxiety and depression and the medication they took to treat these conditions placed them at risk with respect to safety in the workplace. Drawing on the results, the authors outline areas for improvement in the management of mental health problems at work.

Contributing factors in construction accidents.

This overview paper draws together findings from previous focus group research and studies of 100 individual construction accidents. Pursuing issues raised by the focus groups, the accident studies collected qualitative information on the circumstances of each incident and the causal influences involved. Site based data collection entailed interviews with accident-involved personnel and their supervisor or manager, inspection of the accident location, and review of appropriate documentation. Relevant issues from the site investigations were then followed up with off-site stakeholders, including designers, manufacturers and suppliers. Levels of involvement of key factors in the accidents were: problems arising from workers or the work team (70% of accidents), workplace issues (49%), shortcomings with equipment (including PPE) (56%), problems with suitability and condition of materials (27%), and deficiencies with risk management (84%). Employing an ergonomics systems approach, a model is proposed, indicating the manner in which originating managerial, design and cultural factors shape the circumstances found in the work place, giving rise to the acts and conditions which, in turn, lead to accidents. It is argued that attention to the originating influences will be necessary for sustained improvement in construction safety to be achieved.

Manual handling of highway kerbs--focus group findings.

The manual handling of concrete highway kerbs remains commonplace in the construction industry despite obvious risks to operatives. This study was undertaken to find out why kerb installation still includes manual handling, to identify the alternatives that exist and to consider how the organisation of the work affects exposure to risk. Focus groups were held with industry professionals to discuss kerb design, installation and the training of operatives, with site visits and interviews undertaken to place the focus group findings in context. The focus group discussions highlighted manufacturer's "myopia", a lack of installation knowledge of designers and shortfalls in training for installation work. It was concluded that risks to the health of construction workers remain as they are not considered in the design of the product, design of the work or ameliorated by adequate risk assessment. Recommendations from the research are that a pro-active approach to health needs to be adopted by the manufacturers of heavy construction products. Designers of work requiring the use of heavy products need to have more experience of site operations, and education and training in manual handling is desirable at all levels in construction organisations.

Processes, barriers, and outcomes described by ergonomics consultants in preventing work-related musculoskeletal disorders.

Despite the importance of reducing work-related musculoskeletal disorders, there appears to have been little evaluation of routine ergonomics consultancy interventions aimed at reducing risks leading to these conditions. In many instances, the effectiveness of advice depends on organisations accepting and implementing measures recommended, involving changes of both individual and collective behaviour. Behaviour change theory, developed elsewhere, suggests that if change is to take place, recipients need to hold positive attitudes and beliefs relating to the desirable behaviour. To investigate the extent to which this is accommodated by current ergonomics consultancy practices, 14 ergonomics consultants were interviewed to explore the consultancy process from which recommendations are developed, exploring the factors that are assessed by consultants, perceived barriers to promoting change, and the extent to which evaluation of outcomes takes place. Consultants' recommendations generally focused on physical aspects of the work environment and did not take explicit account of employees' knowledge or attitudes. Little evaluation of outcomes was conducted by the consultants interviewed. Implications of these findings for improving the efficacy of interventions to reduce work-related musculoskeletal disorders within organisations are discussed.

Influence of the visual environment on the postural stability in healthy older women.

BACKGROUND: A poor postural stability in older people is associated with an increased risk of falling. It is recognized that visual environment factors (such as poor lighting and repeating patterns on escalators) may contribute to falls, but little is known about the effects of the visual environment on postural stability in the elderly. OBJECTIVE: To determine whether the postural stability of older women (using body sway as a measure) differed under five different visual environment conditions. METHODS: Subjects were 33 healthy women aged 65-76 years. Body sway was measured using an electronic force platform which identified the location of their centre of gravity every 0.05 s. Maximal lateral sway and anteroposterior sway were determined and the sway velocity calculated over 1-min trial periods. Body sway was measured under each of the following conditions: (1) normal laboratory lighting (186 lx); (2) moderate lighting (10 lx); (3) dim lighting (1 lx); (4) eyes closed, and (5) repeating pattern projected onto a wall. RESULTS: Each measure of the postural stability was significantly poorer in condition 4 (eyes closed) than in all other conditions. Anteroposterior sway was greater in condition 3 than in conditions 1 and 2, whilst the sway velocity was greater in condition 3 than in condition 2. Lateral sway did not differ significantly between different lighting levels (conditions 1-3). A projected repeating pattern (condition 5) did not significantly influence the postural stability relative to condition 1. CONCLUSIONS: The substantially greater body sway with eyes closed than with eyes open confirms the importance of vision in maintaining the postural stability. At the lowest light level, the body sway was significantly increased as compared with the other light levels, but was still substantially smaller than on closing the eyes. A projected repeating pattern did not influence the postural stability. Dim lighting levels and removing visual input appear to be associated with a poorer postural stability in older people and hence might be associated with an increased risk of falls.

Targeting ergonomics interventions--learning from health promotion.

Ergonomics often involves encouraging people to accept change, a process affected by their knowledge, attitudes and beliefs. This paper argues that ergonomics projects are likely to have greater success where formal account is taken of these characteristics, and interventions are tailored accordingly. Furthermore, it is suggested that ergonomics can usefully draw upon behaviour change models developed by those concerned with health promotion in the community. One influential model is Prochaska and DiClemente's (Psychotherapy: Theory, Research and Practice, 19, 276-288, 1982) stage of change framework, which describes recipients of health information as progressing through six stages towards stable healthy behaviour: precontemplation, contemplation, preparation, action, maintenance and relapse. This recognises the dynamic nature of behaviour change and that, both within and between individuals, responses may vary from failing to acknowledge existence of a health risk, to where something has already been done about it. Proponents of the model contend that interventions should seek to identify recipients' stage of change and target information and advice accordingly. It is proposed that Prochaska and DiClemente's approach might usefully inform ergonomics activities, particularly when advising with respect to health and safety (e.g. manual handling, upper limb disorders, fall risk, plant safety, etc.) but perhaps also where dealing with other ergonomics considerations (i.e. comfort and performance).

Identification of risk factors and countermeasures for slip, trip and fall accidents during the delivery of mail.

Risk factors for slip, trip and fall accidents (STFA) during the delivery of mail were identified using a range of accident-centred and accident-independent methods. Key factors included slippery underfoot conditions, non-weather related environmental hazards (e.g., uneven paving, steps, inadequate lighting), poor slip resistance from footwear, unsafe working practices, management safety practices, and underlying organisational influences. Intervention measures were recommended that target STFA risks at three levels: slip resistance, exposure to hazardous conditions, and employee behaviour in the face of hazardous conditions. The use of a participative approach to intervention selection and design enabled allowance for the organisational context to be made.

Ergonomics considerations in the design and use of single disc floor cleaning machines.

This study investigated ergonomics issues connected with the use of single-disc floor cleaning machines (buffers/polishers). Methods included interview/questionnaire surveys of users and other groups (maintenance personnel, purchasing managers, manufacturer representatives), along with video analysis. A notable proportion of users (56%) reported discomfort from machine use, mostly musculoskeletal in origin. Main locations were hand (39%), shoulder (19%), wrist (7%), lower back (7%) and arm (6%). Deficiencies were identified with the design and configuration of the handle/operating-switch. Problems were also found arising from the trailing power cable, along with manual handling implications due to machine size and weight. It is concluded there is scope to improve on current designs.

Manual handling risks and controls in a soft drinks distribution centre.

This paper describes an investigation into manual handling risks and controls within a soft drinks distribution centre, presented as a case study regarding compliance with the requirements of the Manual Handling Operations Regulations 1992. Methods used included semi-structured interviews, document analysis, analysis of training, OWAS postural analysis and use of the NIOSH equation. Warehouse operators and delivery drivers were studied, and two methods of work compared involving pallets and cages. Significant differences were found between the two work methods with respect to harmful postures. Manual handling risks were found in both warehouse and delivery areas, some being classed as "excessive" using the NIOSH equation. As this company has a good safety record and considers itself proactive in the area of health and safety, the investigation raises concerns about how organisations have responded to the Manual Handling Operations Regulations.

Slip, trip and fall accidents occurring during the delivery of mail.

This study sought to identify causal factors for slip, trip and fall accidents occurring during the delivery of mail. Analysis of in-house data produced information about accident circumstances for 1734 fall cases. The most common initiating events in delivery falls were slips and trips. Slips most often occurred on snow, ice or grass, while trips tended to involve uneven pavements, obstacles and kerbs. Nearly one-fifth of falls occurred on steps, with step falls requiring longer absence from work than falls on the level. Half of all falls occurred during November-February and three-quarters of falls occurred between 7 and 9 a.m. Incidence rates for female employees were 50% higher than for their male colleagues. Accident-independent methods included interviews with safety personnel and managers, discussion groups with delivery employees, and a questionnaire survey of employees and managers. These techniques provided data on risk factors related to the task, behaviour, footwear and equipment. Arising from these accident-independent investigations, it is suggested that unsafe working practices, such as reading addresses while walking and taking shortcuts, increase the risk of falls. Organizational issues include management safety activities, training and equipment provision. Measures are discussed that might lead to a reduction in the incidence of delivery fall accidents.

Case studies of occupational health management in the engineering construction industry.

Construction workers are exposed to considerable hazards carrying a health risk, e.g., dusts, fumes, noise and manual handling, yet there is often poor occupational health service provision particularly for subcontracted labourers. This paper presents seven case studies from large, engineering construction organizations, concerning current practice in occupational health management. The results supported the fact that data and records regarding health-related absence were limited and inconsistent, and that little existed in terms of medicals and health surveillance, particularly in the case of subcontracted workers. The main difficulties envisaged were reported to be the sizeable costs involved; the temporary and mobile work force; demonstrating cost-benefits to top management and a lack of interest amongst workers, perhaps exacerbated by the threat of lost livelihood. Managers also admitted limited health expertise and knowledge of the wider role health professionals could play in health management. Training and further research in this area are indicated.

Using computer-based models for predicting human thermal responses to hot and cold environments.

Four influential models, capable of predicting human responses to hot and cold environments and potentially suitable for use in practical applications, were evaluated by comparing their predictions with human data published previously. The models were versions of the Pierce Lab 2-node and Stolwijk and Hardy 25-node models of human thermoregulation, the Givoni and Goldman model of rectal temperature response, and ISO/DIS 7933. Experimental data were available for a wide range of environmental conditions, with air temperatures ranging from -10 to 50 degrees C, and with different levels of air movement, humidity, clothing and work. The experimental data were grouped into environment categories to allow examination of the effects of variables, such as wind or clothing, on the accuracy of the models' predictions. This categorization also enables advice to be given regarding which model is likely to provide the most accurate predictions for a particular combination of environmental conditions. Usually at least one of the models was able to give predictions with an accuracy comparable with the degree of variation that occurred within the data from the human subjects. The evaluation suggests that it is possible to make useful predictions of deep-body and mean skin temperature responses to cool, neutral, warm and hot environmental conditions. The models' predictions of deep-body temperature in the cold were poor. Overall, the 25-node model provided the most consistently accurate predictions. The 2-node model was often accurate but could be poor for exercise conditions. The rectal-temperature model usually overestimated deep-body temperature, although its predictions for very hot or heavy exercise conditions could be useful. The ISO model's allowable exposure times would not have protected subjects for some exercise conditions.