  We present a systematic comparison of jet predictions at the LHC and the
Tevatron, with accuracy up to next-to-next-to-leading order (NNLO). The exact
computation at NNLO is completed for the gluons-only channel, so we compare the
exact predictions for this channel with an approximate prediction based on
threshold resummation, in order to determine the regions where this
approximation is reliable at NNLO. The kinematic regions used in this study are
identical to the experimental setup used by recently published jet data from
the ATLAS and CMS experiments at the LHC, and CDF and D0 experiments at the
Tevatron. We study the effect of choosing different renormalisation and
factorisation scales for the NNLO exact prediction and as an exercise assess
their impact on a PDF fit including these corrections. Finally we provide
numerical values of the NNLO k-factors relevant for the LHC and Tevatron
experiments.
