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Some of the frequently asked questions about the what, why, when, how, where and who of statistical quality engineering are discussed. Questions answered include: “What would be an active approach to the objectives of statistical quality engineering?” “How is statistical quality engineering related to Six Sigma?” The concepts, techniques and illustrations, explained in a non‐mathematical language, are useful to both management and technical personnel interested in strategies and tools for cost‐effective quality improvement.

When objective decisions are to be made, statistical methods should be used based on any objective information in the form of data collected about a product or process. Statistical techniques such as control charts, process capability indices and design of experiments have been used in the manufacturing industry for many years. There are a number of practical and managerial issues related to the application of statistical techniques in studies aimed at improving process and product quality. This paper is a summary of the thoughts and discussions from a recent Internet conference on this issue. Statistical process control techniques and their role in process improvement are first discussed and some issues related to the interpretation and use of experimental design techniques are also summarised. The focus will be on continuous quality improvement using statistical techniques.

A variety of quantitative specifications, usually in terms of numerical limits, have been developed in industry for the description, prediction and control of product quality. As the theoretical foundations of these specifications are often beyond the working knowledge of many manufacturing engineers and managers, this article gives a non‐mathematical account of some of the limits commonly encountered in discussions related to product design, manufacture and inspection; emphasis is placed on the distinctions in their intended purposes and methods of application.

Control charts based on geometric distribution have shown to be useful when this is a better approximation of the underlying distribution than the Poisson distribution. The traditional c‐chart, if used, will cause too many false alarms. It is noted that for geometric distribution, the control limits are based on k times standard deviation which has been used previously, will cause a frequent false alarm, and cannot derive any reasonable lower control limits. Studies the use of probability limits to resolve these problems. Also discusses the use of geometric distribution for process control of high‐yield processes.

This paper aims to expand the literature on financial and operational performance by analyzing the effects of undergoing through Six Sigma training.

The effects of implementing Six Sigma trainings is analyzed for 108 Fortune 500 companies. The authors estimate long-term stock returns and 14 financial ratios of Six Sigma companies, both pre- and post-adoption periods. Furthermore, The authors match the 108 companies by size and industry to 108 non-Six Sigma companies also within the Fortune 500.

Looking at long-term stock returns, the evidence shows that Six Sigma firms need at least four years before they start to outperform the controlling sample. Furthermore, looking at operational performance, unlike prior reported results, the authors find supporting, and more importantly, persisting statistical evidence that Six Sigma firms are less liquid and have a negative growth in staff levels in comparison to the matching firms.

The findings of this suggest that if Six Sigma provides any value to the company, it comes at the expense of overloaded staff levels, as evidenced by the fact that Six Sigma firms have less growth in staff levels than the matching firms.

It is one of the first paper to thoroughly investigate the effects on both financial performance and operational performance of spending, sometimes billions of dollars, in Six Sigma training.

Optimal crew allocation and scheduling is an important issue in the management of a large fleet of taxis. Presents a modelling study of a taxi service operation in a Singapore public transport company, with the results adaptable for other similar operations. Proposes two quantitative techniques: the queueing analysis approach and the integer programming approach: These can be used to allocate and schedule the taxi fleet to cover the demand for services at various time periods and geographical zones for the entire country. Presents a routeing and scheduling management information system to support the scheduler in making routeing and scheduling decisions.

Traditional attribute control charts are based on the monitoring of the number of nonconforming items in a sample of fixed size. In modern manufacturing processes, since items can be checked automatically, use of samples of a fixed subjective size with traditional charts is not suitable for on‐line continuous inspection. Furthermore, the sample size usually has to be large when the process fraction nonconforming is not reasonably high. If a decision is to be made only when a sufficient number of items are manufactured and inspected, many nonconforming items might have been produced. In this paper, a control scheme is presented based on the monitoring of cumulative counts of items inspected. This procedure will limit the number of consecutive nonconforming items to a small value when the process has suddenly deteriorated, can detect a sudden process shift quickly and is suitable for continuous inspection processes. The exact probability control limits are derived and the implementation procedure is described.

Exponential distribution is widely used in reliability and maintainability studies although it is well known that the constant failure rate assumption may not be valid. The purpose of this paper is to investigate the use of exponential distribution as an approximation. In fact, for components undergoing regular maintenance or replacement, the exponential assumption can be acceptable. In this paper, the exponential approximation for regularly maintained Weibull component is studied. The approximated exponential distribution using the average failure rate is compared with the exact reliability. The asymptotic relative error is derived, which can be used to adjust the exponential approximation when needed. Based on the framework of exponential approximation for Weibull distributed components, the problems of decision‐making regarding the optimal maintenance time and spare allocation are also addressed.

The attainment of superior quality and reliability in a manufactured product depends upon the existence of a framework integrating an organization’s capabilities in management, technology and information utilization. With respect to information utilization, statistical tools are particularly essential for optimizing product and process performance. This paper outlines the functions of these tools and examines the steps in which they are adopted by non‐statisticians in industry. A “seven S” approach is explained, highlighting a strategy for the effective deployment of statistical quality engineering.

The purpose of this paper is to review Lean Six Sigma (LSS) literature and report different definitions, demographics, methodologies and industries.

This paper highlights various definitions by different researchers and practitioners. A total of 235 research papers has been reviewed for the LSS theme, research methodology adopted, type of industry, author profile, country of research and year of publication.

From the review, four significant LSS classifications were identified that deal with the spread of LSS in different industries followed by observation for classification.

LSS is a strategy for success, but it did not examine its presence in various Industries. From this paper, readers can understand the quantum of its spread before implementing LSS. For academicians, it will be a comprehensive list of papers for research.

This paper reviews 235 research papers for their year, author profile, research methodology and type of industry. Various characteristics of LSS definitions and their theme are also reviewed.