Various types of phenomena contribute to the variability of process results. Their common feature is randomness. Some of them can be described by continuous probability distributions, for example, the performance of machines or the properties of processed material. There are also discretely distributed contributions, such as human errors or machine failures. Six sigma methodology encompasses both continuous and discrete phenomena by expressing measures of variability by the so-called 'sigma measure'. However, this methodology cannot be used directly to assess the individual impact of a specific class of factors, such as human errors in a continuously distributed production process. This paper describes the development of a probabilistic model of human error. The model makes use of classical reliability concepts, such as a failure rate function, to represent substantial phenomena of various types (continuous and discrete) that play a significant role in the creation of errors in human work. The model includes a mechanism that is inherently associated with human work (i.e. the 'bathtub curve' that represents the processes of learning and fatiguing) and mechanisms introduced by the work environment (accumulation of tasks). The hypothesis is formulated that, in industrial processes, special causes of errors are closely related to the assignment of inadequate amounts of time for properly performing the operations. Graphs of error rate functions enable intuitive graphical interpretation of the causes of problems, and they can be used to support some considerations regarding the organization and measurement of workflow during a work shift. Thus, an intuitive graph can be useful for figuring out the potential impact on the risk of errors that will result from certain system events. Such graphs can be applied in a general capability study of a process to assess the variability measures associated with the individual impacts of particular classes of factors, for example, the sigma measure used in the six sigma methodology. It can be used to identify mechanisms of potential failures associated with human error in risk analysis, such as FMEA (Failure Mode and Effect Analysis).

Purpose Health care is an example of an organization where the needs of potential clients are much greater than the capabilities of the service delivery system. The implementation of any medical procedure, as well as the provision of any service, just like the manufacturing of any product, can be decomposed into a series of tasks. The purpose of this paper is to propose a model for measuring the effectiveness of quality assurance tasks in health-care delivery processes. Design/methodology/approach The authors analyze a system of factors that affect the implementation of tasks in a process. In their considerations, they have focused on four areas of science that describe conditions that are related to the implementation of tasks: Scheduling as a methodology for allocating resources to perform tasks; Capacity planning as a methodology for assigning values to given resources expressed by the number of tasks that can be executed with the resources; Queueing theory, used as a methodology for describing phenomena in which not all planned tasks are performed within the prescribed specification limits; and Quality management, as a methodology to ensure appropriate conditions for completing tasks (CCTs), where CCT is a representation of parameters of casual relationship between variables. Findings The authors show that the effectiveness of executing any scheduled tasks in the process is determined by the difference between the capacity of resources allocated (at a given time interval) and the number of tasks planned to be carried out at that time. The CCT conditions determine the level of capacity of the fixed amount of resources. It is shown that their deviation from the reference CCT specification may cause the nominally correct amount of resources be either too small (causing queue formation and longer wait time in hospitals) or too large to contribute to the waste in the system by creating idle capacity. Practical implications The scope of application of the model is wide. It covers tasks performed with different degrees of uncertainties regarding the capacity of resources. It applies in all areas of health care where unlike manufacturing, the services delivered and the tasks performed in the health-care delivery system are seldom identical. Every patient is treated differently than the one waiting next in line. The workloads are pre-arranged in the order they are needed and completed in accordance with the FI-FO (first in-first out) principle. The model presented in this paper makes it possible to better understand the mechanism of effectiveness and efficiency improvement and the role of humans as a specific carrier of capacity. Originality/value As most of the health-care organizations are still stuck in the soft side of quality assurance, there has been little research conducted to test the applicability of well-known productions/operation management methodologies and theories benefitting health-care systems. The formulation of a reference point of CCT in this study is to serve as a stabilizing control point with t...

Purpose The paper presents a process of development of the capacity of resources used in the improvement of an organization. The purpose of this paper is to determine the conditions in which the development of the improvement capacity is sustainable. Design/methodology/approach As the basis for the study, the following prerequisites have been adopted: potential effects of the use of resources in a process can be expressed by their capacity, which involves the productivity and volume of the resources; a model of sustainability of improvement is based on the procedure ABC and principle of continuous improvement; an improvement process involves two components: subject matter (eliminating problems) and methodical (learning how to eliminate problems during the execution of subject matter tasks) projects; the methodology of Six Sigma can be a reference model, which is studied to identify and interpret elements and relationships that are characteristic for the process of sustainable development. Findings There have been formulated a model of the process of developing the improvement capacity in which the subject matter and methodical tasks are coupled, a model of the Six Sigma process that refers to the features of the process of development of the improvement capacity and three principles for sustainable development of improvement capacity. Originality/value The principles refer to decisions on the improvement process made at basic (strategic, tactical and operational) levels of an organization.

PurposeThe purpose of this paper is to establish a procedure to examine an organization's improvement process and its adverse factors.Design/methodology/approachThe objectives were to find a way to represent content of a specific improvement process and analyse reliability of improvement processes conducted at operational, tactical and strategic levels. Inspirations of the text were various heuristic schemes used in a process of problem solving: to stimulate transfer of data by formulation of questions (5W or 5Why); to control the flow of the process (QC Story or 8D etc.); and to document results of operation (Ishikawa, fault‐tree diagram, and others). The outcomes are: a questioning scheme on Improvement Story by 5 Whys, which provides guidance, through a study of an organization's improvement processes related to containment, corrective and preventive type; and diagrams of the Prevention State Transitions and the Improvement Snail, which facilitate navigation through the above processes.FindingsThere is a finite sequence of Why‐questions, which can be used to analyse basic characteristics of systems of improvement processes in organizations. This scheme has a direct graphical representation in the Improvement Snail and the Prevention States Transition diagrams.Practical implicationsThe scheme has a wide scope of applications: it can be used retrospectively or in parallel to a running process of problem solving. A context of the analysis may be auditing an improvement process or monitoring a particular improvement project.Originality/valueThe scheme combines various aspects of improving the effectiveness of an organization's functions. It can represent, in a systematic way, information concerning risk issues related to: the problems and their mechanisms; the effectiveness of improvement processes that are related to various levels of organization: operational, tactical and strategic and their coordination. The scheme is flexible, as it can be combined with various analytical techniques such as fault tree diagram etc. and it can be adjusted to any specific purpose, by modifying the structure and content of questions set.

Purpose The purpose of this paper is to find determinants of the effectiveness of the business improvement processes that create value for services offered to patients in healthcare industries. The words patients and customers are used interchangeably throughout without any distinction. The features that distinguish medical services of different types and their inter-related factors are examined. The aim is to come up with a model of value vs cost that can help healthcare managers examine and use this exercise as an example of improvement micro-projects to help reduce cost and eliminate the patient’s dissatisfaction gaps. Design/methodology/approach The list of factors or attributes influencing the creation of value of a given medical process or a single procedure is described. The factors in the value creation are examined that will help in the categories for the risk analysis to determine the value-added benefits for the patient outcome. The cost analysis is approached from two angles to include: the cost of the service, and the costs of poor quality of service. Findings The model describes the value for the patient satisfaction depending on the quality level or grade of the treatment or procedures used and the cost factor. The analysis is done at several levels with special reference to case examples. A search for various analogous models in similar service providing situation used in business process management of other process types is highlighted and discussed. Originality/value The model is an interesting generic illustration for considering value vs cost in all patient care strategies. It enables the position of various medical procedures that can be applied to the same disease in order to keep the variations as minimum as possible within the quality control specification limits. The importance in different aspects of check-points or hold points for inspection is also discussed.