  We revisit the problem of searching for gravitational waves from inspiralling
compact binaries in Gaussian coloured noise. For binaries with quasicircular
orbits and non-precessing component spins, considering dominant mode emission
only, if the intrinsic parameters of the binary are known then the optimal
statistic for a single detector is the well-known two-phase matched filter.
However, the matched filter signal-to-noise ratio is /not/ in general an
optimal statistic for an astrophysical population of signals, since their
distribution over the intrinsic parameters will almost certainly not mirror
that of noise events, which is determined by the (Fisher) information metric.
Instead, the optimal statistic for a given astrophysical distribution will be
the Bayes factor, which we approximate using the output of a standard template
matched filter search. We then quantify the possible improvement in number of
signals detected for various populations of non-spinning binaries: for a
distribution of signals uniformly distributed in volume and with component
masses distributed uniformly over the range $1\leq m_{1,2}/M_\odot\leq 24$,
$(m_1+m_2) /M_\odot\leq 25$ at fixed expected SNR, we find $\gtrsim 20\%$ more
signals at a false alarm threshold of $10^{-6}\,$Hz in a single detector. The
method may easily be generalized to binaries with non-precessing spins.
