Purpose – The purpose of this paper is to study the effect of correlation on the performance of CUSUM and EWMA charts. The performance of the CUSUM and EWMA charts is measured in terms of average run lengths (ARLs) for the positively correlated data. The ARLs at various set of parameters of...

Purpose – The purpose of this paper is to counter autocorrelation by designing the chart, using warning limits. Various optimal schemes of modified chart are proposed for various sample sizes ( n ) at levels of correlation (Φ) of 0.00, 0.475 and 0.95. These optimal schemes of modified chart...

Purpose – Many companies can today attest to having obtained significant progress in their performance using some improvement processes (six sigma, 5S, business process reengineering, etc.). But they can also attest to experiencing difficulties in sustaining the use of these processes over...

Purpose – The purpose of this paper is to propose a methodology that may assist quality professionals in assessing process variation with a combination of tools based on simple robust statistics. The technique targets alternative way of screening and detection of common and special causes in...

Purpose – The purpose of this paper is to implement statistical process control (SPC) in service quality using three-level SERVQUAL, quality function deployment (QFD) and internal measure. Design/methodology/approach – The SERVQUAL questionnaire is developed according to internal services of...

Purpose – The purpose of this paper is to propose a set of process capability indices (PCIs) which are based on robust and agile statistics such that they may be applicable irrespective of the process status. Design/methodology/approach – The four popular PCIs – Cp, Cpk, Cpm and Cpmk –...

Purpose – The recent expansion in tertiary education in India, an increased student enrollment as well as global competition have created a challenge for the existence of the institutes. It has been realized that a quality of service is associated with customer satisfaction and it is one of...