Applying hierarchical task analysis to improving the patient positioning for direct lateral interbody fusion in spinal surgery

The present study brings together for the first time the techniques of hierarchical task analysis (HTA), human error identification (HEI), and business process management (BPM) to select practices that can eliminate or reduce potential errors in a surgical setting. We applied the above approaches to the improvement of the patient positioning process for lumbar spine surgery referred to as ‘direct lateral interbody fusion’ (DLIF). Observations were conducted to gain knowledge on current DLIF positioning practices, and an HTA was constructed. Potential errors associated with the practices specific to DLIF patient positioning were identified. Based on literature review and expert views alternative practices are proposed aimed at improving the DLIF patient positioning process. To our knowledge, this is the first attempt to use BPM in association with HEI/HTA for the purpose of improving the performance and safety of a surgical process – with promising results.     

A process centered analysis of medication administration: Identifying current methods and potential for improvement

Medication administration is an increasingly complex process that requires adaptability by nurses. In this study, twenty-one observational sessions of the medication administration process were conducted on a Medical/Surgical unit, and the processes used by nurses were analyzed to discover systemic process variability and determine possible best practices. When nurses instituted a patient medication order and medication review cycle prior to the other activities associated with medication administration, it was more likely that discrepancies in physician orders, electronic medication administration records, and missing medications would be mitigated within the same medication pass.

Relevance to industry

This research specifically investigates the process flows involved in medication administration This work is a starting point in an effort to establish industry best practices and to identify the variables, such as technology use, facility layout, and process interruptions, which impact their standardization.     

Improving the usability of intravenous medication labels to support safe medication delivery

Medication label design is frequently a contributing factor to medication errors. Design regulations and recommendations have been predominantly aimed at manufacturers’ product labels. Pharmacy-generated labels have received less scrutiny despite being an integral artifact throughout the medication use process. This article is an account of our efforts to improve the design of a hospital’s intravenous (IV) medication labels. Our analysis revealed a set of interrelated processes and stakeholders that restrict the range of feasible label designs. The technological and system constraints likely vary among hospitals and represent significant barriers to developing and implementing specific design standards. We propose both an ideal IV label design and one that adheres to the current constraints of the hospital under study.

Relevance to industry

Hospitals are tasked with creating customized medication labels with minimal guidance. Our process, findings, and proposed labels provide insight for similar investigations at other institutions.     

Learning to make errors: evidence from a driving task simulation

Human errors represent a mismatch between the demands of an operational system and what the operator does. If they cannot be reversed, their consequences may be severe. Errors are frequently classified as design-or operator-induced. A third class of errors may also be identified, namely process-induced errors. Such errors arise out of on-going processes which typically extend over time. One such process is that of learning. In relation to the acquisition of skills, for example, learning frequently involves a trial-and-error component. Accidents by inexperienced drivers may represent a severe consequence of such errors. Errors may also arise out of particular learning experiences which provide a distorted underestimate of objective risk and/or motivate high risk behaviour. These phenomena are investigated in a computer simulation of the driving task. The relationship is discussed between various kinds of learning experience and the development of situations in which the possibility of error recovery declines. Some suggestions for reducing the frequency of irreversible errors and for increasing the data base for human error in vehicle driving are made.     

A taxonomy of human communication errors and application to railway track maintenance

This paper proposes a communication error taxonomy that takes into account both the aspects of communication which are unique to human performance and those which can fit into broader human error classifications. Relevant taxonomy elements are applied to communication errors related to railway track maintenance. The analysis was based on communication data captured from voice recordings of conversations between signallers and trackside personnel. The recordings were transcribed and then classified in relation to communication topic and error types. These data provide a better understanding of the communication process and also provide human error probability data for use in human reliability assessment.     

Variable errors set a limit to adaptation

This paper argues that variable error introduces a limit to the extent to which a person can be adapted to his or her environment in general, and for the extent to which the driver can be adapted to the traffic environment in particular. This is because variable error turns what is a deterministic and stable world into an uncertain one where it is only possible to be adapted in a statistical sense. A series of experiments are then discussed. These experiments show that drivers match their utilization of perceptual information to the validity of this information, i.e., they treat uncertainty introduced by variable error in the perceptual system in the same manner as they treat uncertainty in the physical system. This supports the main hypothesis of the paper. A driver may mitigate the effects of variable error by having a safety margin, but the relation between speeds and accident rates (predicted from the current hypothesis) shows that this adaptation is not effective enough. Safety authorities may mitigate the effects of variable error by decreasing the variability of the driving environment, e.g., by introducing speed limits.     

Violations and errors during simulation-based driver training

The effectiveness of virtual driving instruction can increase when techniques that automatically distinguish between violations and errors are available, two behaviours requiring different types of remediation. This study reports the analysis of the objectively measured performance of 520 participants completing a simulation-based training programme. Factor analysis of failure reasons showed that violations and errors were the primary underlying factors. Men committed more violations and women made more errors; the magnitude of sex differences corresponded to the factor loadings. Factor analysis of the mean task completion times yielded a factor that can be described as the extent to which motivation for speed resulted in quicker task execution. Quicker participants completed more tasks, committed more violations, but made fewer errors. Participants reduced errors during forced-paced driving and increased speed during self-paced driving. The authors would recommend exploiting the distinction between violations and errors by developing interfaces and feedback for both types of aberration.     

Validating task analysis for error identification: reliability and validity of a human error prediction technique

This paper reports on the theoretical and empirical developments for an error prediction methodology called task analysis for error identification (TAFEI). Other researchers have noted the need for theoretically driven approaches that are able to provide practical utility in error prediction. Theoretical developments include the concept of ‘rewritable routines’, which describe the loop between cognitive processing, action and devices states. This has been proposed as a way of unifying ideas from systems theory and cognitive psychology. The empirical research shows that TAFEI is superior to heuristic methods, which supports the idea that structured methods assist in error prediction. The validation study shows that TAFEI reaches acceptable levels in terms of test – retest reliability and concurrent validity. It is believed that the method has reached a level of maturity after 10 years of development work. This is demonstrated by the many uses to which the method has been put, including that of a design tool.     

Relations between task and activity: elements for elaborating a framework for error analysis

The notion of error, when applied to an activity or the result of an activity, implies the notion of task: it expresses the deviation between the activity and the task being considered from an angle which is judged to be relevant. The task and the activity are the object of representations for the analyst (or specialist) and for the driver. Four representations are dealt with in this paper: the task and the activity for the specialist and the task and the activity for the driver. An interpretation is proposed for these tasks, and they are illustrated using some of the work already carried out in this field. The signification of deviations between these representations is then discussed, together with the advantage of studying these deviations in order to clarify error-producing mechanisms. Analysis in terms of task and activity raises methodological and practical problems which are touched upon; it does not exclude referring to psychological theoretical frameworks to which it is worthwhile linking it. This perspective raises questions which make it possible to enhance the study of errors: it could be completed at a later date by extending it to include other representation categories.     

A statistical analysis of syntax errors

A study of errors made by Pascal programmers is described. The results of this study are discussed in relation to compiler syntax error recovery procedures. It is found that syntax errors made in practice are quite simple and occur relatively infrequently (generally at most one per sentence of the language). Also a few types of errors account for most occurrences. These and other findings from the study are helpful in evaluating compiler error handling procedures. A discussion of the relation between these errors and language constructs is presented. Other uses of the information obtained from the study are briefly described.     

A simulation-based embedded probe technique for human-computer interaction evaluation

There is growing interest in developing video-based methods to evaluate the usefulness and usability of computerised tools in healthcare. In this paper, we propose a human-computer interaction evaluation method that protects the confidentiality of patient information and reduces litigation risks for participants by embedding and analysing performance on probes in complex scenarios with high face validity in a simulated setting. We describe the application of the method to a series of three studies of bar code medication administration (BCMA) software, used to reduce medication errors in the Veterans Administration.     

Predicting numerical data entry errors by classifying EEG signals with linear discriminant analysis

Daily numerical data entry is subject to human errors, and errors in numerical data can cause serious losses in health care, safety and finance. Difficulty in detecting errors by human operators in numerical data entry necessitates an early error detection/prediction mechanism to proactively prevent severe accidents. To explore the possibility of using multi-channel electroencephalography (EEG) collected before movements/reactions to detect/predict human errors, linear discriminant analysis (LDA) classifier was utilised to predict numerical typing errors before their occurrence in numerical typing. Single trial EEG data were collected from seven participants during numerical hear-and-type tasks and three temporal features were extracted from six EEG sites in a 150-ms time window. The sensitivity of LDA classifier was revealed by adjusting the critical ratio of two Mahalanobis distances as a classification criterion. On average, the LDA classifier was able to detect 74.34% of numerical typing errors in advance with only 34.46% false alarms, resulting in a sensitivity of 1.05. A cost analysis also showed that using the LDA classifier would be beneficial as long as the penalty is at least 15 times the cost of inspection when the error rate is 5%. LDA demonstrated its realistic potential in detecting/predicting relatively few errors in numerical data without heavy pre-processing. This is one step towards predicting and preventing human errors in perceptual-motor tasks before their occurrence.     

Micro- and macroergonomic changes in mental workload and medication safety following the implementation of new health IT

Health information technology (IT) is a promising way to achieve safer medication management in the delivery of healthcare. However, human factors/ergonomics dictates that in order to make the complex, cognitive work of healthcare delivery safer, health IT must properly support human cognition. This means, for example, that new health IT must reduce, not increase, workload during safety-critical tasks. The present study was the first to quantitatively assess the short- and long-term impact of bar coded medication administration (BCMA) IT on nurses' mental workload as well as on perceived medication safety. One-hundred seventy registered nurses across 3 dissimilar clinical units at an academic, freestanding pediatric hospital in the Midwest US participated in surveys administered before, 3 months after, and 12 months after the hospital implemented BCMA. Nurses rated their external mental workload (interruptions, divided attention, being rushed) and internal mental workload (concentration, mental effort) during medication administration tasks as well as the likelihood of each of three medication safety events: medication administration errors, medication errors on the clinical unit, and clinical unit-level adverse drug events. Clinical unit differences were assessed. Findings generally confirmed the hypothesis that external but not internal mental workload was associated with the perceived likelihood of a medication safety event. Comparisons of mental workload from pre- to post-BCMA revealed statistically significant changes in the critical care unit only. Medication safety appeared to improve over the long term in the hematology/oncology unit only. In the critical care and medical/surgical units, medication safety exhibited short-term improvements that were eliminated over time. Changes in mental workload and medication safety, two classically microergonomic constructs, were deeply embedded in macroergonomic phenomena. These included the fit between the BCMA system and the nature of nursing work, the process of BCMA implementation, and BCMA interactions with concurrent changes occurring in the hospital. Findings raise questions about achieving sustainable performance improvement with health IT as well as the balance between micro- and macroergonomic approaches to studying technology change.Relevance to industryDesigners must consider how technology changes cognitive work, including mental workload. Hospitals and other implementers of technology must ensure that new technology fits its users, their tasks, and the context of use, which may entail tailoring implementation, for example, to specific clinical units. Evaluators must look over time to assess both changes in cognitive work and implementation issues. Healthcare practitioners must also recognize that new technology means a complex transformation to an already complex sociotechnical system, which calls for a macroergonomic approach to design and analysis.     

Drivers' errors in,and out of,context

Error depends for its definition, commission, and the seriousness of its consequences on the circumstances in which it occurs. As such, it is argued, in this overview of a large number of contemporary papers on (driver) error, that an erroneous act is only a useful index of behaviour where the background to that act is properly understood. The role of error in the development of skill, and its relationship to accident causation and risk-taking is discussed from this point of view.     

Construction errors as a key to perceptual difficulties encountered in reading technical drawings

A large number of subjects drawn from a variety of populations was required to build simple models in response to diagrams. Their responses were evaluated with especial reference to the errors made. It seems that the errors were largely due to misperception of the drawings and therefore show what difficulties people are likely to find when required to use technical drawings. These difficulties range from inability to perceive elementary units correctly (a weakness characteristic of the least educated/sophisticated subjects) to inability to group the relations among such units. Examples of errors made are discussed and their significance for training in the usage of technical drawings stressed.     

Applying agglomerative hierarchical clustering algorithms to component identification for legacy systems

Context

Component identification, the process of evolving legacy system into finely organized component-based software systems, is a critical part of software reengineering. Currently, many component identification approaches have been developed based on agglomerative hierarchical clustering algorithms. However, there is a lack of thorough investigation on which algorithm is appropriate for component identification.

Objective

This paper focuses on analyzing agglomerative hierarchical clustering algorithms in software reengineering, and then identifying their respective strengths and weaknesses in order to apply them effectively for future practical applications.

Method

A series of experiments were conducted for 18 clustering strategies combined according to various similarity measures, weighting schemes and linkage methods. Eleven subject systems with different application domains and source code sizes were used in the experiments. The component identification results are evaluated by the proposed size, coupling and cohesion criteria.

Results

The experimental results suggested that the employed similarity measures, weighting schemes and linkage methods can have various effects on component identification results with respect to the proposed size, coupling and cohesion criteria, so the hierarchical clustering algorithms produced quite different clustering results.

Conclusions

According to the experimental results, it can be concluded that it is difficult to produce perfectly satisfactory results for a given clustering algorithm. Nevertheless, these algorithms demonstrated varied capabilities to identify components with respect to the proposed size, coupling and cohesion criteria.     

Contextualising design: Aspects of using usability context analysis and hierarchical task analysis for software design

Usability Context Analysis is part of ISO 9241-11 and, as such, is recommended for use in user-centred design. However, studies involving a critical assessment of usability context analysis within the software domain are scarce; this paper details two small studies that involved the use of usability context analysis (UCA) and hierarchical task analysis (HTA). The first system involved designing a small subsite of a larger website, while the second system was a small database designed as part of an exercise by UK university students. Post-design evaluation suggested that the use of both UCA and HTA, rather than one or the other, was beneficial in gathering and analysing user requirements.     

Contextualising design: Aspects of using usability context analysis and hierarchical task analysis for software design

Usability Context Analysis is part of ISO 9241-11 and, as such, is recommended for use in user-centred design. However, studies involving a critical assessment of usability context analysis within the software domain are scarce; this paper details two small studies that involved the use of usability context analysis (UCA) and hierarchical task analysis (HTA). The first system involved designing a small subsite of a larger website, while the second system was a small database designed as part of an exercise by UK university students. Post-design evaluation suggested that the use of both UCA and HTA, rather than one or the other, was beneficial in gathering and analysing user requirements.     

Suggestions on the applicability of visual instructions with see-through head mounted displays depending on the task

Task instructions have traditionally been communicated orally in many fields. However, recently more and more wearable displays, such as the see-through head mounted displays (HMDs) have been developed, and some studies have provided ideas on applying visual instruction using these new interfaces to particular situations. However, in some cases, where instructions are communicated amongst the workers, the data is not sufficient for field workers to choose the best way of communicating instructions depending on the situation. Thus, this study aims to clarify the cases in which it is effective to apply visual instructions with HMDs, and to provide information that suggests the applicability of such visual instructions instead of or in addition to the traditional auditory instructions in different situations. These suggestions will be a useful reference for workers in safety-critical fields, helping them make better decisions about whether, when, and where to introduce the new method of instructions. It will also address some of the unsolved problems in the field, such as errors, low efficiency, and discomfort in communication.