A synthetic control chart for the coefficient of variation

A new exponentially weighted moving average control chart for monitoring the coefficient of variation

“…Castagliola et al (2013b) proposed a Shewhart chart with supplementary run rules to monitor the CV. However, as they pointed out, the run rules charts for monitoring the CV does not outperform more advanced strategies like the chart proposed by Castagliola et al (2011) or the synthetic chart proposed by Calzada and Scariano (2013).…”

“…CV: coefficient of variation; MCV: modified chart for monitoring CV (this paper proposed); ECV: EWMA chart for monitoring CV (Castagliola et al, 2011); SynCV: synthetic chart for monitoring CV (Calzada & Scariano, 2013); SRCV: Shewhart chart with supplementary run rules for monitoring CV (Castagliola et al, 2013b); UCL: upper control limit; LCL: lower control limit; UWL: upper warning limit; LWL: lower warning limit; IC: in-control; OC: out-of-control; ARL: average run length; ZS-ARL: zero-state average run length; SDRL: standard deviation of the run length.…”

“…Recently, Calzada and Scariano (2013) developed a synthetic control chart for monitoring the CV. The results showed that the synthetic chart performed better than that of Kang et al (2007), but worse than Castagliola et al (2011) as long as the increasing shift in the CV is not too large.…”

Monitoring the coefficient of variation using a variable sample size control chart in short production runs

“…More recently, Castagliola et al [3] suggested a new method to monitor the CV by means of two one-sided EWMA charts of the CV squared. Calzada and Scariano [4] suggested a synthetic control chart (denoted SynCV) for monitoring the CV, and Castagliola et al [5][6][7] proposed alternative approaches to monitor the CV based on Run Rules, Variable Sampling Interval (VSI), and Variable Sample Size (VSS) strategies, respectively.…”

Variables two stage sampling plans based on the coefficient of variation

“…Tool cutting life and several properties of sintered materials are typical examples from this setting. More recently, it has received increasing attention in statistical quality control, one can refer to Kang et al (2007), Calzada and Scariano (2013), and Castagliola et al (2015). For instance, Tong and Chen (1991) proposed the variable single sampling plan considering the CV as the quality parameter for normal distribution.…”