  The commonly used detection test statistic for Cherenkov telescope data is Li
& Ma (1983), Eq. 17. It evaluates the compatibility of event counts in an
on-source region with those in a representative off-region. It does not exploit
the typically known gamma-ray point spread function (PSF) of a system, and in
practice its application requires either assumptions on the symmetry of the
acceptance across the field of view, orMonte Carlo simulations.MAGIC has an
azimuth-dependent, asymmetric acceptance which required a careful review of
detection statistics. Besides an adapted Li & Ma based technique, the recently
presented generalized LRT statistic of [1] is now in use. It is more flexible,
more sensitive and less systematics-affected, because it is highly customized
for multi-pointing Cherenkov telescope data with a known PSF. We present the
application of this new method to archival MAGIC data and compare it to the
other, Li&Ma-based method.
