  Interferometric gravitational-wave detectors like LIGO, GEO600 and Virgo
record a surplus of information above and beyond possible gravitational-wave
events. These auxiliary channels capture information about the state of the
detector and its surroundings which can be used to infer potential terrestrial
noise sources of some gravitational-wave-like events. We present an algorithm
addressing the ordering (or equivalently optimizing) of such information from
auxiliary systems in gravitational-wave detectors to establish veto conditions
in searches for gravitational-wave transients. The procedure was used to
identify vetoes for searches for unmodelled transients by the LIGO and Virgo
collaborations during their science runs from 2005 through 2007. In this work
we present the details of the algorithm; we also use a limited amount of data
from LIGO's past runs in order to examine the method, compare it with other
methods, and identify its potential to characterize the instruments themselves.
We examine the dependence of Receiver Operating Characteristic curves on the
various parameters of the veto method and the implementation on real data. We
find that the method robustly determines important auxiliary channels, ordering
them by the apparent strength of their correlations to the gravitational-wave
channel. This list can substantially reduce the background of noise events in
the gravitational-wave data. In this way it can identify the source of glitches
in the detector as well as assist in establishing confidence in the detection
of gravitaional-wave transients.

Instrumentation and Methods for Astrophysics