  We review methods for monitoring multivariate time-between-events (TBE) data.
We present some underlying complexities that have been overlooked in the
literature. It is helpful to classify multivariate TBE monitoring applications
into two fundamentally different scenarios. One scenario involves monitoring
individual vectors of TBE data. The other involves the monitoring of several,
possibly correlated, temporal point processes in which events could occur at
different rates. We discuss performance measures and advise the use of
time-between-signal based metrics for the design and comparison of methods. We
re-evaluate an existing multivariate TBE monitoring method, offer some advice
and some directions for future research.
