| Vol.1/2004 |
Forms of control as buffer of the relationship between job demands and strain Support potential of different media for the early stages of engineering design
|
| Vol.2/2004 |
Perception and assessment of artificial indoor lighting Two studies of the role of light spectrum in visual performance Online Event Recording in Task Analysis Breathing, attention and distraction as a function of emotional stimuli Environmental ergonomics: Odors emitted by industry Exposure to particles in occupational situations and in the environment
|
| Vol.3/2004 |
Work ability among nurses in hospitals in Germany in the European context On-call service in German hospitals: an analysis of doctors’ work-related stress and strain Cooperation in anesthesia teams as seen by the team membersCooperative Development of Display and Interface-Concept for an Anaesthesia-Respirator
|
| Vol.4/2004 |
Assessment of learn-promoting job design for customer-consultants in a call center
|
|
Forms of control as buffer of the relationship between job demands and strain (Vol. 1 - 2004) Authors: Klaus-Helmut Schmidt Keywords: Forms of control · buffer hypothesis · strain
indicators · work organization and Summary Karasek's (1979) job demands-control model of job strain has strongly
influenced the research on the relationship between work and health. The
model is based on two psychosocial job characteristics that are
considered as important determinants of a wide range of health-related
outcomes. The first characteristic includes job demands conceptualized
as psychological stressors like, for example, having to work under time
pressure, and having to cope with complex, mentally exacting tasks. The
second one relates to the degree of control that employees have over
their tasks and behaviors in performing the daily work. The model
assumes that strain not only results from main or additive effects of
demands and control but, in addition, from an interaction between both
job characteristics in which control buffers or moderates the adverse
effects of job demands on strain. Practical Relevance The results of the present study suggest that measures for preventing geriatric nurses from being strained should especially be directed to increase the opportunity of determining the scheduling of their work. This would enable the nursing staff to timewise organize their work in a way that is adjusted to their actual needs and circumstances.
Authors: Marc Baumgartner & Ivars Udris Keywords: Call Center tasks · training and continuous education · personnel development · job satisfaction Due to the developments in the technology and the market, working
conditions and requirements for competences of Call Center Agents (CCA)
are changing. Frequently neglected career planning and missing job
perspectives can be considered as causes for high fluctuation rates and
job dissatisfaction. Meanwhile Call Center Managers und human resources
specialists are aware of the importance of the personnel development,
depending on the different Call Cen-ter types and personnel structures
of Call Centers (CC). The following research questions are therefore to
be answered: What are the main and the additional tasks of the CCA? How
the tasks can be differentiated in useful types? How different are the
personnel structures among the CC types? What are the most important
reasons for choosing the CC job? Which are the measures of personnel
development taken in the diffe-rent CC types? Which are the consequences
of the personnel development on the personnel structures and on the
state of the employees? How the CC types can be differentiated
concerning job satisfaction, commitment and fluctuation tendency of the
CCA? How work load and organizational resources have an impact on the
state and behavior of the employees? On the basis of semi-structured
interviews, questionnaires, observations and document analyses with 13
CC Managers, 20 CC Teamleaders and 242 CCA 14 Swiss CC from different
branches were examined. Practical relevance A typological distinction of the work activities in CC has consequences on the management and organization of the tasks, on the initial training, the continuous education and the development of the CC employees.
Support potential of different media for the early stages of engineering design (Vol. 1 - 2004) Authors: Martina Schütze Keywords: · Engineering design · design problem solving · sketching · interactive pen display · CAD Due to its economic importance, engineering design as a demanding and
complex problem- solving activity has been the subject of
interdisciplinary research of both psychologists and design scientists
for several years. In particular, the early stages of problem
clarification and conceptual design are of significant interest.
Decisions made within these phases are most decisive for the resulting
product quality and costs; but the effects of these decisions are only
vaguely calculable (Ehrlenspiel 1995). The following dependent variables were recorded: - variables concerning the results: quality of the solution, communication of the technical information content (expert evaluation with evaluation schemes, Schütze 2003), total solution time; - variables concerning the subjective experience: experienced difficulty of the design problem, certainty of the correctness of the solution, psychic stress (all measured using bipolar ratingscales); - variables concerning the process: percentage shares of activities relative to solution time and changes of activities, percentage shares of design steps relative to their total number and changes of designing steps (recorded with video and/or computer-aided protocol techniques), solution generation: generation vs. correction procedure. Selected results are evaluated: No significant differences could be
found between the two groups designing by free-handsketching with paper
& pencil and with pen display, neither in the variables concerning the
results and the subjective experience nor in selected shares of
activities and the solution generation. This speaks well for comparable
demands of these two media on the user. Practical Relevance Pen Displays seem to be excellent for supporting engineering design using classical and digital media within the meaning of an interactive and integrated communication unit. They can open a large potential concerning competitive time and cost savings as well as innovations for the process of product development.
Authors: Gert Zülch, Mikko Börkircher & Sascha Stowasser Keywords: · Knowledge Management · Communication Ergonomics · Personnel Assignment · User-Friendliness · Evaluation · Visualization In order to exploit the potential of information technology, software
systems should be adapted to the cognitive requirements of the users. In
a project of the Collaborative Re-search Centre 346 "Computer-Integrated
Design and Manufacturing of Parts" at the University of Karlsruhe it has
been determined and experimentally examined which forms of visualization
are suitable for the user-equitable representation of experience
knowledge. The exemplary development of a user-friendly, object-oriented
tool for the planning of short-term personnel assignment serves to
demonstrate possible visualization forms. Based on already realized
tools, which (suggest and) attempt to capture the knowledge in
structures and processes within the area of knowledge-based systems, and
the configuration approaches, rules and conclusions from earlier
research work within the Collaborative Research Centre 346 a prototypic,
knowledge-based decision support system for short-term personnel
assignment was developed. The goal within the system was to visualize
knowledge in a user-friendly manner to support users in their decisions
and thus to help them to discover solutions for disturbance situations. Practical relevance An important task in the supply of data for construction and
manufacturing processes through knowledge-based systems can be seen in
the user-friendly configuration of the human- omputer- interface. This
interface ensures the exchange of process related data, information and
knowledge between the user and information system within a dynamic
context of the process flow.
Perception and assessment of artificial indoor lighting (Vol. 2 - 2004) Authors: Christoph Schierz Keywords: Indoor lighting · luminance · perception · affective assessment · attribution · mental construct SUMMARY It is well known that photometric assessment of a lighting system is not sufficient to produce indoor illumination that fulfills user expectations. The reason is that light not only causes objects to become visible, a function which is measurable. It also acts as a carrier of information. Lighting systems need to fulfill the following requirements to perform these two functions adequately: ¨ They must not cause inconvenience, for example, through glare, inadequate luminance, shadow or flicker. All these factors can be determined photometrically. ¨ They must improve comfort. Light should help to arrange information sources in the user’s physical environment. For example, lighting can emphasize important information (eye-catchers) or it can draw attention to or simulate desired associations (e.g. private -public). Perceived comfort is greater if these associations match the user’s expectations. The aim of this study was to design a method of assessment of well-being (emotion) and the creation of associations (attribution). Methodology We constructed a model linking the objective physical world with the subjective psychological world. The core of the model is the visual perception of a "mental construct system". We assumed that subjects do not assess the objective world directly, but more probably through the perceptual part of the mental construct system. This model has been tested experimentally. So-called "lighting scenarios" were used as the objective world. The scenarios are realistic stereoscopic pictures of various types of interior lighting projected by a special slide viewer. The varying reactions to these lighting scenarios from 21 subjects were recorded using mutual comparison (multidimensional scaling), a verbal questionnaire and factor analysis. Results The results show that the model of a mental construct system can be concretized. We were subsequently able to establish a connection between the lighting scenarios and the perceptual part of the mental construct system on one hand, and between this part of the system and the subjective assessments on the other. Conclusions The question is how the findings can be applied to illumination planning practice. It is the planning concepts, not the planning tools, which need to be modified. These concepts should be evolved at planning stage of a building and be based on a joint mental construct system containing input from all parties involved (architect, builder-developer, lighting engineer, user, etc.). Practical relevance Increasing pressure to save energy is leading to concentration of illumination on the visual tasks at the workplace, whilst the walls and ceiling of a room tend to get left in the dark. However, experience and basic research shows that light from the whole field of vision is important for biological and psychological well-being. New guidelines for indoor light distribution are needed to satisfy these requirements. Guidelines defining requirements for workplace illumination alone are not sufficient. This study examines some of the fundamentals of the psychological effects of light with the aim of defining these additional guidelines.
Two studies of the role of light spectrum in visual performance (Vol. 2 - 2004) Authors: Marino Menozzi Keywords: yellow filter · night driving · mesopic vision · display · chromatic aberration · dynamics of accommodation Summary Prof. Krueger has paid particular attention to various aspects of "vision at work" during his 20 years at the Institute of Hygiene and Applied Physiology (IHA). This report starts by summarizing scientific research and developments at the IHA relating to vision at work and goes on to present findings from two unpublished studies, which also demonstrate the breadth of the methodical approach used by Professor Krueger in his investigations. Study 1: Yellow filters for night driving Background: Yellow filters, for which it is claimed that they reduce glare from headlights of oncoming vehicles at night, are available on the market. It is not clear how they are supposed to achieve this effect because the light transmission through these filters (approx. 80%) is too high to effectively reduce headlight luminance. We conducted a study using the recommendations of the German Ophthalmologic Society to assess mesopic acuity (ability to see in the twilight range). Measurements were performed with and without yellow filters and with and without a glare source. Method: A total of 25 subjects took part in the first experiment. Subjects performed a test aiming to assess mesopic acuity. Mesopic acuity defines the luminance contrast required to pass a given acuity test successfully under mesopic conditions. A Nyktometer 500 instrument was used for this purpose. Mesopic acuity was assessed with and without yellow filters in random order. Measurements were then repeated in the presence of a glare source incorporated into the Nyktometer 500. Results: In general, we can state that the yellow filter does not improve mesopic acuity under either one of the experimental conditions. On the contrary, yellow filters were found to reduce mesopic acuity in several cases. Conclusions: We cannot recommend the use of yellow filters, as our findings failed to reveal any improvement in measured visual function when they are worn. As with other lenses, yellow filters may constitute a potential risk under certain circumstances: the quality of the filter can deteriorate with time (e.g. because of surface scratches) and the frame and the filter itself could cause additional injuries in an accident. Study 2: Spectral distribution of light and accommodation dynamics Background: Many sources of artificial light are used nowadays at workplaces and also during leisure activities. Chromatic aberrations in the human eye caused by the spectral content of this light can adversely affect accommodation. Previous studies have demonstrated the effect of a particular spectral distribution on static accommodation function. The dynamics of accommodation are an important factor determining visual performance at many workplaces. For example, flight controllers frequently need to adjust viewing distance. In this second study we investigated the effect of a narrow band light source (light-emitting diodes) on the dynamics of accommodation. Method: Seven subjects took part in the second experiment, which involved continuous recording of accommodation during performance of a task in which the test person had to focus successively on objects situated at two different distances, which were known to the test person. Three different narrow-band light sources (red, blue and yellow-green) were used. Dynamic performance was expressed in terms of speed and latency of accommodation. Results: In general, we found no statistical significant correlation between latency and speed of accommodation and spectral distribution of the light source used. Slight differences in performance were found when comparing results obtained with the yellow-green (586 nm) light source to those obtained with the red (635 nm) and blue (470 nm) sources. Conclusions: In a task where an observer focuses on objects situated at a known viewing distance, narrow band light sources such as those found in light-emitting diodes, e.g. in traffic lights, do not give rise to dynamic accommodation problems. It is not known whether these results could be repeated in a study involving a larger number of subjects (e.g. 100). It seems possible that yellow-green light could affect performance. Practical relevance The first study shows that yellow filters claiming to reduce headlight glare cannot be recommended for night driving. The second study shows that visual displays using light-emitting diodes (e.g. traffic lights, large-format or head-mounted displays) do not affect the dynamics of accommodation.
Online Event Recording in Task Analysis (Vol. 2 - 2004) Authors: Jürgen Held Keywords: Online Event Recording · Task Analysis · Time-Line Analysis Summary The following article discusses current techniques and methods used to record and analyze work processes, and introduces an event recording technique known as Flexible Interface Technique (FIT System). The article touches on subjects like definition of task categories and design of the event recorder interface, and discusses the interactive capabilities of the various techniques. It demonstrates that the FIT System provides more flexibility and capacity in recording and analyzing observed events. Most event-recording techniques on the market today have predefined interface design structures. They offer only a limited range of symbols and only one syntax for user interaction with the portable handheld computer (personal digital assistant, PDA). Nor do they support installation of additional graphic design elements at the user interface. A further problem is that the majority of currently available event recording techniques do not allow the user to make changes to the interface design when online or in the field. Instead, the interface has to be defined in advance on a personal computer before downloading to the portable PDA. This is because the user interface is part of the event recording software and also because of the PDA’s limited data input storage capacity. Unlike other recording techniques, the FIT System’s interface is not integrated into the software. It is in the form of a detachable, transparent overlay. The user/observer can design his own interface manually (i.e. by drawing it) without having to interact directly with the PDA’s software. Symbols, icons and other graphical or typographical information can be set out as required on the overlay without having to make use of the PDA’s limited ability to display contrast, symbols, and colors. When recording spatially variable events, observers can establish a relationship between the observed space and the interface overlay by producing their own diagram of the environment being observed and analyzed. This is possible because users/observers can arrange symbols and graphic elements at will on the transparent overlay. Another useful design feature enables users to create simple, clear interface prototypes online by adding more symbols or icons to the interface during the recording process. Users can handle between 40 and 70 task categories (events) with the FIT System, register high-frequency parallel events (multi-tasking) and register individually allocated and shared tasks in teamwork analysis. The analysis then requires a method for combining illustration of the individually recorded event sequences. A solution of this problem is presented in the form of a diagram in which each event appears as a vector, with the event category being assigned to the angle of the vector and the event duration to the length of the vector. Practical Relevance Event recording and analysis play an important role in ergonomic systems design. The work described in this article can help to improve online coding and review and analysis of observed events. The FIT System will enable human factors specialists to analyze a system’s behavior more efficiently and effectively.
The Ergonomics of Interaction (Vol. 2 - 2004) Authors: Daniel Felix Keywords: Human-Machine Interaction · Usability · ticket vending machine · development process Summary Modern technology is influencing our everyday lives to an ever increasing extent. For many years now, research at the Institute of Hygiene and Applied Physiology at the ETH in Zurich has focused on how to facilitate use of this technology by members of the lay public. Whilst the importance of classical ergonomics in this process was realized at an early date, it soon became clear that new methods and procedures were needed to meet the ergonomic challenges of modern technology. Health was no longer the crucial aspect. It was now more a question of understanding and being able to use modern technology in the proper way. Graf (1988) conducted studies analyzing eye movements in his research into man-computer interaction. This technique was later refined and applied with great success by other groups at the Institute (Menozzi 1991). It has always been the Institute’s policy to test theoretical work in a practical context. Eye-movement analysis was used in a user interface evaluation of a ticket-vending machine for the Zurich passenger transport network (ZVV). It demonstrated that the user interface has a significant influence on success rate and process time. It included both laboratory and field tests with real users and compared two different solutions to the problem. The findings revealed that users had no problems buying their tickets if a known element like the postal code is used for encoding destinations, with a numerical ten keypad for entering this code, and if the successive procedural steps are arranged from left to right and top to bottom. The laboratory and field-testing procedures were later standardized and are now regularly used. Further studies in this area were conducted over the subsequent years. With the support of the Swiss research foundation KTI a touch-screen experimental ticket-vending system for the Federal German Railway was developed. Individual components of the user interface were tested. A 10-key pad received the best rating for entering figures (e.g. the number of travelers) and a calendar page for entering dates. No preference could be discovered for entering destination or departure station. The top-rated solution used an alphanumeric keypad on the screen and progressively reduced the number of hits with each press of the key. There was also a design study in which screen layouts were compared (Felix & Krueger 1993a). Users were found to prefer a clear structure and color scheme. The full project is described in Felix (1997). These results were later used for the development of the touch-screen ticket-vending machines now used by the Swiss Railways (SBB). Other studies followed as part of the EU-funded Project ESSAI (Paulillo et al.1995; Felix & Krueger 1993c). An interactive public kiosk was developed selling theatre tickets (for the Arena di Verona), cinema tickets in a field experiment in Milan and last-minute holidays in a second field experiment in Basle. These yielded a large number of new findings. The vending system’s user interface and location must reflect the nature of the goods and services being sold. For example, high-end theatre tickets are difficult to sell from a vending machine located on the street. Useful information and supporting information (e.g. design elements) must be clearly separated and the useful information must be easily identifiable. Further research on icon recognition (Breinholt 1998) revealed that icons are most easily recognized if they are not too complex, have a clear outline and use an abstract rather than a photographic symbol. The thesis presented by Manzke (1999) investigated the problem of digital divide, namely, ways of refining an automated teller machine (ATM) for use by blind and visually impaired persons. He found that a linear concept with an easy-to-use menu structure was not only beneficial for the target group but also for non-handicapped users. No technical problems arose with the experimental system during live operation for three months in a Swiss bank. Sadly, the concept was never put into practice. The Institute is actively pursuing its work on development and evaluation of user interfaces for public use. It is the only scientific institution in Switzerland offering independent evaluation of usability and user acceptance of interfaces. The knowledge gained over the years is passed on in courses held at the ETH and Zurich University and at various other universities of applied sciences. It is important to sensitize students to this topic, because developers and project managers will not pay sufficient attention to this problem unless they are made more aware of the importance of the human factor. The foundation of the ETH usability lab in the Zurich Technopark in 1994 was a logical extension of all these activities and projects. It was here that a development process for interactive systems was defined (Felix 1997; Felix & Krueger 1993b) which was later found to be very similar to the ISO 13 407 standard development process. Its projects were so successful that it was decided in 2001 to form a spin-off company named ergonomie & technologie. This company is now operating profitably and will be separated from the Institute this fall. One of e&t’s developments is the e&t attentiontracker® which measures the speed and order in which elements of an Internet page catch the users’ attention (Disler et. al. 2003). This involves a tachistoscopic procedure in which users report the element seen. The procedure can provide more evidence on how information is perceived. An increasing amount of research and consulting work on user interfaces will become necessary in the future, because this will be the only way in which modern technology can be handled and exploited successfully. It is therefore essential for the Institute of Hygiene and Applied Physiology to continue its tradition in this field, because the work is of great social and scientific value and there is still much to do. Current work in the field of driving simulation (Uhr 2004) is a good example of this. The really important thing is to make maximum possible use of technology without losing sight of the needs of the people who are supposed to benefit from it. Cost-effectiveness is another important factor. This underlines the importance of selecting the appropriate technology to attain the set objectives. These objectives should no longer be the typical former ones - ‘faster’, ‘more’ and ‘more attractive’. The ideal objectives in the modern-day world are ‘more useful’, ‘simpler’ and ‘more convenient’. Practical Relevance Modern technology can only be successfully exploited and used efficiently and effectively if it is understood by users. A user-oriented development process and neutral evaluation of the quality of use offered by a new product development can significantly improve product quality.
Authors: Sissel Guttormsen Schär Keywords: Ergonomics · Software Ergonomics · technological evolution · research · knowledge models · human factors in HCI · measurement of usability Summary Rapid technological development results in new challenges for the ergonomics field. The technological development involves new challenges concerning the implementation of usability by exploiting the new technical possibilities, e.g. by developing new user-centered aims for methods of work, enabling new forms of interaction, and developing new cognitive and emotional models for human computer interaction (HCI). We suggest four guiding principles for further research and development in the field of software ergonomics: 1. The priorities for software ergonomics research need to be re-formulated 2. Knowledge & models for applied perception and information processing need continuous re-evaluation 3. A shift from technology driven to human factors driven HCI design is due 4. New methods for measurement of usability are necessary.
Practical Relevance This paper gives an overview over the actual challenges and possibilities for software ergonomics given by new technological development. Four suggested guiding principles for research propose actual priorities and offer applied examples of new forms of interaction.
Authors: Thomas Läubli Keywords: workload · musculoskeletal disorders · regeneration Summary In order to design health-oriented, ergonomic work activities, it is essential to know the limits at which a given workload becomes an overload and constitutes a health hazard. The relationship between exposure and hazard need not to be linear. Underload can also constitute a health hazard. A "U" –shaped relationship between exposure and a worker’s internal strain is often postulated. Under-load may result in monotony, loss of interest, diminished muscular strength or deterioration in physical fitness. Excessively high exposures may induce fatigue and ultimately cause health problems. It is therefore assumed that an average load is optimal. A relationship, which is approximately parabolic, may also be modeled by two separate functions. One function would be valid at a low sensory and psychosocial flow of information, indicating that focusing places ever increasing demands on the subject at low sensory load levels. The second function would describe increased stress as information flow and demands for decision increase. Both approaches lack the dimension of time and no allowance is made for important questions like accumulation, fatigue, recuperation and regeneration. Winkel & Westgaard (2001) pointed out that recent economic changes have had a strong influence on time structures at work and that more attention should be paid to the effect of this trend on worker health. There is evidence indicating increased productivity and improvements in ergonomic design of workplaces. It is also reasonable to assume that the incidence of heavy work and repetitive assembly tasks has decreased. Despite this, stress reactions and musculoskeletal pain remain prevalent complaints. For example, research by Maul et al (2003) showed that work tasks in nursing have dramatically changed within the last ten years. The number of patients cared for by a single nurse has doubled, but the number of beds per nurse has dropped by a factor of two. However, the prevalence of regional musculoskeletal disease has remained more or less unchanged. The frequency of these complaints may perhaps be explained by the fact that workers have become more involved in the work process and that there is less downtime caused by production line breakdowns or sub-optimal work organization. We have demonstrated continuous activity of single motor units for at least 30 minutes during computer work. Activity frequently continued during short interruptions of the task itself and during short breaks (Zennaro et al. 2003b). Thus, individual motor units may be subjected to high loads even when demands on muscle activity are relatively small. There are indications that these loads tend to cause fatigue and possibly overload. Recuperation may also be adversely affected. It is postulated that investigation of the time structure of internal strain on single organs and of the regeneration periods required by them could help to explain the reasons for the continuing occurrence of this type of disorder. Practical Relevance Research into the time needed for organ recovery and regeneration may help to prevent musculoskeletal disorders.
Breathing, attention and distraction as a function of emotional stimuli (Vol. 2 - 2004) Authors: Brigitta Danuser & Patrick Gomez Keywords: Arousal · attention · distraction · emotion · respiration · valence Summary Several lines of research indicate that emotional experiences are basically organized around the affective dimensions of valence and arousal. Valence and arousal are conceived as two independent bipolar dimensions forming a two-dimensional affective space. Valence, also called pleasure or pleasantness, summarizes a person’s well-being. Arousal, also called activation at the level of subjective experience, describes a sense of mobilization or energy. Recent work has provided evidence for a correlation between physiological variables (heart rate, skin conductance, facial electromyography, brain activity, blink reflex) and the emotional dimensions of valence and arousal. However, very few studies have investigated the relationship between respiration and these emotional dimensions, even though most of the available data suggest that respiration patterns may reflect general dimensions of emotional response. To extend our knowledge of the respiratory response during affective processing, we conducted two studies to investigate respiratory responses to emotional stimuli. Specifically, we sought to determine whether and to what extent there is any covariance between respiratory measures and hedonic valence and arousal level of the selected stimuli. Visual and auditory stimuli were chosen as emotion elicitors, because these are of the greatest significance for the general public, e.g. exposure to magazines, television, Internet, films and music. Static pictures were used in the first study. The second study used environmental noises and musical passages. Different reactivity patterns would suggest type-specific modulation (visual vs. acoustic stimulation), whereas similar patterns would indicate activation of a common emotional system. All the stimuli were of 30-second duration. Respiration was measured non-invasively with inductive, volume-calibrated, respiratory plethysmography. Respiration was analyzed in detail, including a number of parameters, which are thought to give an insight into the mechanisms regulating breathing. Skin conductance level and heart rate were also measured. The results of these studies suggest that arousal plays a central role in the respiratory response to affective stimuli. Subjective reports of arousal were found to co-vary with several breathing parameters. In particular, increases in the arousal level of all stimulus categories were accompanied by increases in minute ventilation. This relationship was chiefly due to shortening of the time parameters as arousal increased, whereas inspiratory volume showed no relation to either valence or arousal ratings. The relationship between valence and respiration was less clear-cut and appeared to be much more stimulus-dependent than that found with arousal. No respiratory parameter was found to co-vary consistently with valence and no specific relationships to valence were observed. In summary, these studies support the contention that breathing responses are organized to a certain degree along the affective dimensions of valence and arousal. In a third study, the role of emotional valence in task distraction was investigated by exposing the participants to two pleasant and two unpleasant odors during performance of a demanding multiple task consisting of three sub-tasks: a tracking task, a short-term memory task and a reaction task. The advent of the unpleasant odors was accompanied by prolongation of inspiration and a decrease in mean inspiratory flow in the first five breaths after odor onset. We are of the opinion that these respiratory changes reflect a shift of attention resources from the task to the unpleasant odors and represent the respiratory equivalent of the orienting response to odors. Longer inspiration and decreased inspiratory flow prolong the duration of odor processing and thus enable better interpretation and evaluation of a potentially harmful olfactory stimulus. Performance of the memory task (recognition of a specific color sequence "green – blue – red" of a constantly changing moving circle), was markedly decreased in the presence of the unpleasant odors. One plausible explanation for this specific deterioration in performance is that processing of the odors and recognition of the color sequence require the same cognitive resources. Information has to be accumulated over a certain period of time before an odor’s quality and intensity can be properly interpreted. Similarly, the last two colors have to be kept in mind to decide whether or not the sequence is correct when the third color appears. In summary, changes in respiration and deterioration in performance indicated that unpleasant odors distracted the participants from their task. Practical Relevance Modern work forms make high demands on our attention, memory, mental concentration, learning aptitude, and also on our perception, experience and regulation of emotions. Our research provides information on how humans react to significant affective stimuli and may be of value for future research in applied fields such as human communication, occupational health and human-computer interaction.
Environmental ergonomics: Odors emitted by industry (Vol. 2 - 2004) Authors: Markus Hangartner Keywords: odor assessment · olfacotmetry · ambient odor · odor annoyance Summary Olfactometry measures the acuity of a person’s sense of smell and his or her olfactory threshold for selected odors. Odoriferous samples are diluted with odorless air until the test person can no longer detect the odor. The dilution threshold is a measure of odor concentration. This is a convenient technique for quantifying the success of attempts at odor abatement in an industrial plant. A procedure using a series of olfactory measurements taken at different sites was designed to obtain information on the potential level of environmental nuisance to be expected from odorant industrial emissions. Surveys in the form of questionnaires sent to each household were performed to determine the perceived level of nuisance in the vicinity of several odor-emitting industrial plants. A response rate of between 50 and 70% was achieved after follow-up with a reminder. An 11-point rating scale was used to measure the perceived level of nuisance. The average scores obtained in any given area, based on a minimum of not less than 20 valid returned questionnaires, were used to determine the perceived level of odor nuisance. The results obtained in the different studies were compared and an evaluation procedure analogous to that used for noise investigations was designed. Areas exposed to industrial odor emissions with mean subjective ratings higher than 5 are deemed to suffer an intolerable nuisance level, whereas no nuisance exists in areas with a rating lower than 3. The frequency of odor events emanating from specific industrial plants over a given period of time was regarded as a suitable method for assessing exposure to ambient odor. This type of frequency investigation is only valid if data is obtained from a representative sample and the observations are randomized but equally distributed over the time period. These conditions were satisfied by using non-resident observers performing field inspections to a given time schedule. Although there is a correlation with the perceived level of nuisance as determined by public survey and odor frequency, the results also show that equal odor frequencies may evoke different perceived nuisance levels in the affected population, depending on the hedonic nature of the odor (pleasant/unpleasant), the subject’s attitude to the source of the emission and his or her feeling of helplessness. Practical Relevance Denser development is bringing residential areas and industrial zones closer to each other. The result is an increasing incidence of complaints from populations living in the vicinity of odor-emitting industrial plants. Olfactometric measurements are an effective way of evaluating the success of measures taken to reduce odor emission and enable pragmatic estimates of their capacity to abate environmental nuisance caused by industrially emitted odors. A survey technique enables authorities to assess the perceived level of nuisance in the surrounding population and the results can be used as a basis for imposing restrictions on the industry causing the odor. An inquiry technology enables authorities to assess the degree of annoyance in residents and is the base for imposing conditions to the industry causing odours.
Exposure to particles in occupational situations and in the environment (Vol. 2 - 2004) Authors: Christian Monn & Michael Riediker Keywords: Exposure · Particles · Occupational Health · Environment · Pollutants Summary Airborne particulate matter is a form of pollutant involving a high health risk. Environmental and occupational studies regularly report a clear association between exposure to airborne particles and disease. Airborne particles are a complex group of substances. They can be characterized physically (by mass, size, number or surface area), chemically (sulfates, nitrates, silicates, metals, organic and inorganic carbon compounds, etc.) and biologically (bacteria, pollen, spores and products emanating from them, e.g. endotoxins, allergens etc.). Particles have been shown to cause many different deleterious effects on health. These include "classical" diseases like silicosis (excessive exposure of lungs to silicates resulting in chronic inflammation and ultimately fibrosis). More recently, associations have been established between cardiovascular disease and short-term (daily) exposure to particulate matter (especially to particles originating from combustion processes). Finally, specific microorganisms and/or endotoxins produced by them can attach themselves to airborne particles and cause infections (e.g. legionnaire’s disease) or allergic reactions. This article discusses assessment of levels of exposure to airborne particulate matter in three different cases: biogenous particles in the waste treatment industry, fine particulate matter in outdoor and indoor environments and particles bearing allergenic pollens. These three examples are used to examine state-of-the-art measurement methods for particulate matter: 1) classical bacteriological measurements (waste treatment), 2) size-selective sampling and subsequent gravimetric measurements combined with simple speciation (e.g. fine soot) and 3) highly specific determination of individual compounds (specific allergenic proteins bound to different sizes of particles). There are indications that future particle research will tend to pay closer attention to more refined determination of physical, chemical and biological characteristics of airborne particles. It is hoped that this will yield better understanding of particle characteristics and better understanding of their consequences for health. Practical Relevance Good understanding of particle characteristics will facilitate investigation of pathologic processes associated with airborne particles and development of protective strategies. This article reviews work performed at Prof. Dr. Dr. Helmut Krueger’s institute and points to new trends in particle research.
Work ability among nurses in hospitals in Germany in the European context (Vol. 3 – 2004)Authors: Bernd Hans Müller, Hans-Martin Hasselhorn Keywords: · work ability · nurse · hospital · ageing SUMMARY Introduction: The concept of work ability in Europe has received increased attention in the last 20 years. Work ability refers equally to an individual, business management and economical resources. In view of demographic developments and the associated increasing need for care, this is particularly the case for nurses. In most European countries, nurses retire from the profession early, often earlier than other professions. In order to cover the future need for nurses it will be necessary to retain nurses in the profession. The internationally used Work Ability Index (WAI) registers with 10 questions individual and organisational aspects of work ability (with the use of a questionnaire). The WAI has proven to be predictive in regard to later inability to work, mortality and quality of life. In doing do it is a suitable instrument to estimate future work ability of particular professional groups. The European NEXT-Study (www.next-study.net) is investigating the early retirement of nurses in 10 countries. The study enables a European comparison of work ability in nursing to be made. Method: For the present analysis data was gathered from exactly 23000 qualified nurses, who were employed in hospitals in Belgium, Finland, France, Germany, Great Britain, Italy, the Netherlands, Norway, Poland and Slovakia. Results: The WAI mean scores were highest in Norway (42.2) and the Netherlands (41.7), and lowest in Poland (37.3), France (38.1) and Germany (38.3) (possible WAI range: from 7 (no working ability) to 49 (maximal work ability). This ranking of countries was found for almost all age groups. In the German sample the younger nurses on average had a relatively low WAI mean, which can be accounted for by the low personal judgement of individually perceived work ability in regard to the working demands. From the age of 50 the WAI once more greatly decreased. Low work ability was visibly associated with the desire to leave from the nursing profession early; this meant for the younger nurses a change of occupation, for the elder nurses early retirement. Conclusion: The extent to which relatively low work ability was shown even in younger qualified nurses in German hospital is surprising. The consequence for the younger nurses is the escape from the nursing profession. To ensure an adequate number of nurses on a long-term basis, interventions are necessary which can already be put into practice for the younger nurses. On the other hand, strategies have to be developed to structure the working conditions in such a way that even older nurses with reduced work capacity can continue working in the nursing profession. That this is possible was shown from the nurses from Finland, where despite low WAI scores on average, the older nurses remain in their profession, with comparatively higher work satisfaction. PRACTICAL RELEVANCE In Germany, the low scores for work ability can be attributed to a relatively large discrepancy between the individually perceived own work ability and the work demands, which was the case for all age groups. To ensure a sustainable and sufficient supply of nurses, interventions are necessary which should even be put into practice for younger staff.
Author: Sandra Peter Keywords: · Work values · Work time conditions · Residents and attending physicians (RP and AP) · Differential job design · Emotionale exhaustion · Aversion to clients · Structural equation modeling SUMMARY The objective of the present study is to produce an integrative approach to the concepts of work-related value orientations and differential job design (Ulich et al. 1980, Ulich 2001) using the example of work time. Consequences of not-fulfilled value orientations are examined taking preferences regarding work time as an example. Here it is useful to turn to concepts from the psychological research on stress and to view not-fulfilled expectations regarding work time as stressors. The investigation tests the following hypotheses: (1) Subjectively experienced deficits will have an additional explanatory value aside from stressors and following Leiter’s (1993) model (2) emotional exhaustion will mediate the relation between deficits, or stressors, and aversion to clients. Specific stressors were captured following Rimann (1999). The questionnaire tapped the subjective importance of 31 aspects related to work as well as physicians’ corresponding degree of satisfaction regarding fulfillment of those aspects in their current work situations. The difference between ascribed importance and satisfaction yielded a discrepancy value (deficit), which is understood as a stress factor. Task-related, social and time pressure stressors were assessed using the five-point scales from the “SALSA” questionnaire (Salutogenetische Subjektive Arbeitsanalyse, i.e., Salutogenetic Subjective Work Analysis) by Riman und Udris (1997). Two scales from Hacker und Reinhold’s Stresses and Strains Screening in Human Services (1999) were used to measure strains: “emotional exhaustion” and “aversion to clients.” The degree of agreement was captured on a seven-point scale, ranging from “disagree completely” to “agree completely.” The empirical database for this investigation was generated in hospitals. The sample consisted of 306 residents in physician training programs and attending physicians (62.4% men and 34% women). To test the hypotheses, structural equation modeling was used. For estimation of the likelihood of the parameters, the maximum likelihood method (ML) was implemented. Under all of the deficit factors found, the work time-related deficit factor plays an outstanding role in explaining (and in the emergence of) emotional exhaustion and aversion to clients in residents in training. In addition, deficits in social relationships and valuation contribute significantly to explaining emotional exhaustion. The relevant factors found stand in a linear relationship to emotional exhaustion and aversion to clients. This means that the score on strains increases with increasing deficits, and low deficits, or increased options, lead to lower scores on strains. Not-fulfilled expectations as to work time conditions, not-fulfilled expectations concerning social relationships and valuation, and not-fulfilled expectations as to career, success, and prestige have as much a direct influence on emotional exhaustion in residents and attending physicians as do percentage of employment (full-time, part-time), stressors experienced in performing tasks, and experienced time pressure. A test of interaction effects between deficits and stressors indicates that deficits do not measure the same thing as stressors. The deficit factor values found thus contribute further towards explaining emotional exhaustion. The results confirmed the moderating effect of emotional exhaustion on the relation between deficit factors and aversion to clients for the deficit factor work time. In this case the effect is a true mediating effect, that is, the relation between work time-related deficit and aversion to clients occurs exclusively via emotional exhaustion. As to the mediating effect of emotional exhaustion on aversion to clients in the context of the stressor scales, the following picture emerged: The relationships between stressors (work task stressors, social stressors, and time pressure stressors) and aversion to clients are mediated entirely by emotional exhaustion. Practical relevance All in all, the findings of the investigations confirm – for the conditions of extremely long working hours – the central role of the deficit factors found as well as the outstanding role of deficit regarding work time preferences in the generation, or explanation, of emotional exhaustion and aversion to clients. The findings yield indications that knowledge about and consideration of individual, work-related values – as the source of individual motivations to act, as goals to be achieved in the work setting – provide important leverage for differential job design. Not the consideration of each individual work time-related desire, but the offer of various (value-oriented) work time models could be a possible design approach. Already the offer of a broader - at the most frequent needs oriented – selection of work time models (partial time models, sharing models) as well as the establishment of participation-oriented planning of work time schedules could be meaningful interventions.
Authors: Susanne Merkel, Beate Streit & Peter Richter Keywords: · work-relates stress · strain · on-call service · doctors · hospital SUMMARY German hospital doctors’ chronic states of exhaustion as a result of extensive on-call services, unpredictable working hours, and numerous overtime indicate an acute need for action. The European Court of Justice reacted by ruling that ”on-call duty performed by a doctor where he is required to be physically present in the hospital must be regarded as constituting in its totality working time” (C-151/02) – contrary to present German law. Against this background, a study was conducted in two hospitals in Saxony in cooperation with the Saxony State Ministry for Economic Affairs and Labor. The purpose of this study was to analyse the job-related stress and strain situation of medical doctors and to investigate from a work psychology viewpoint whether on-call service should be regarded as working time. Doctors were asked to keep a stress diary (e.g. Richter et al. 2002; Zijlstra & van Doorn 1985) in order to assess their work activities and strain process during regular work, on-call service and free time. In addition, psychological work load (Büssing et al. 2002) and long-term outcomes like job satisfaction, physical complaints (de Jonge 2001) and burnout (Schaufeli et al. 1996) were analysed. Eighty-seven doctors participated in the study. The strongest sources of psychological work load reported by the doctors were problems with ward occupancy, time pressure, work interruptions, and information insecurity. Problems resulting from patient characteristics and severity of illness were not rated as very stressful. Thus, general work conditions appeared to be more stress-relevant to the doctors than work conditions specific to the medical profession. Analysis of work activities revealed that doctors’ working hours were not only in conflict with European law, but also with German law, as doctors spent more than half of their on-call time working. There was no difference between work activities during the evening part of on-call duty (4 pm – 10 pm) and work activities during regular work (7am – 4 pm), suggesting that doctors were not on-call but merely continuing with their regular work. Only the activities during the night part of on-call duty (10 pm – 7 am) corresponded to an actual on-call service. As strain process analyses showed, there was a significant increase in effort and fatigue and decrease in positive mood during a work day with subsequent on-call duty. After on-call duty, doctors reported significantly higher levels of effort and fatigue and lower levels of positive mood than during regular work before on-call duty, indicating that doctors did not get enough rest during the night on-call. Comparisons between the strain process during work (regular work and on-call duty) and the strain process during a non-work free day confirmed that changes in effort, fatigue and positive mood could not merely be attributed to regular circadian variation. The results of this study support the European Court of Justice decision, that on-call duty performed by hospital doctors should be considered working time. Practical relevance Putting the European Court of Justice decision into action will confront German hospitals with immense costs and a shortage of qualified doctors. However, the health and safety of hospital doctors (for whom it is not unusual to work continuously for more than 30 hours) and their patients need to be protected. The methodology presented in this article is suitable to support hospitals in their need for structural change and the development of innovative working time models.
Cooperation in anesthesia teams as seen by the team members (Vol. 3 – 2004)Authors: Enikö Zala-Mezö, Barbara Künzle, Johannes Wacker, Gudela Grote Keywords: · Explicit vs. implicit coordination · Teamwork · heedful interrelating · standardization · task load SUMMARY This article presents the results from a qualitative interview analysis asking anesthesia team members about work processes, standardization in anesthesia, teamwork, and leadership. The interview analysis was part of a project studying the effect of standardization and task load on coordination processes. The idea behind the entire project is that organizations working in high-risk environments have to fulfill very high quality norms. Additionally they have to handle high levels of complexity and uncertainty. Standardization is a tool on the organizational level to make the work system’s behavior predictable and controllable. However it is not clear how standards interact with the team processes. This interview analysis allowed for gathering the subjective view of the team members about those questions. We used the functional leadership model from Zaccaro et al. (2001) to create a coding system for analyzing the interview material. The main idea of that model is that teams have to integrate 4 crucial team processes to achieve success and team leaders can influence team behavior through influencing those processes: 1. cognitive processes; 2. motivational processes; 3. affective processes; and 4. coordination processes. Data
|
|