  Since the launch of the Fermi Large Area Telescope in 2008 the number of
known ${\gamma}$-ray pulsars has increased immensely to over 200, many of which
are also visible in the radio and X-ray bands. Seyffert et al. (2011)
demonstrated how constraints on the viewing geometries of some of these pulsars
could be obtained by comparing their observed radio and ${\gamma}$-ray light
curves by eye to light curves from geometric models. While these constraints
compare reasonably well with those yielded by more rigorous single-wavelength
approaches, they are still a somewhat subjective representation of how well the
models reproduce the observed radio and ${\gamma}$-ray light curves.
Constructing a more rigorous approach is, however, made difficult by the large
uncertainties associated with the ${\gamma}$-ray light curves as compared to
those associated with the radio light curves. Naively applying a
${\chi}^{2}$-like goodness-of-fit test to both bands invariably results in
constraints dictated by the radio light curves. A number of approaches have
been proposed to address this issue. In this paper we investigate these
approaches and evaluate the results they yield. Based on what we learn, we
implement our own version of a goodness-of-fit test, which we then use to
investigate the behaviour of the geometric models in multi-dimensional phase
space.
