The automatic collection and increasing availability of health data provides a new opportunity for techniques to monitor this information. By monitoring pre-diagnostic data sources, such as over-the-counter cough medicine sales or emergency room chief complaints of cough, there exists the...

The time-between-event (TBE) charts are used to monitor the failure rate λ by examining the time interval T between events. This article proposes a two-sided CUSUM chart (the balanced two-sided CUSUM chart) for detecting both increasing and decreasing shifts in λ. The performance studies show...