Monitoring processes with data censored owing to competing risks by using exponentially weighted moving average control charts

In industry, process monitoring is widely employed to detect process change s rapidly. However, in some industrial applications observations are censor ed. For example, when testing breaking strengths and failure times often a limited stress test is performed. With censored observations, a direct appl ication of traditional monitoring procedures is not appropriate. When the c ensoring occurs due to competing risks, we propose a control chart based on conditional expected values to detect changes in the mean strength. To pro tect against possible confounding caused by changes in the mean of the cens oring mechanism we also suggest a similar chart to detect changes in the me an censoring level. We provide an example of monitoring bond strength to il lustrate the application of this methodology.