  We analyze the reliability of several techniques for computing jet and hadron
spectra at different collision energies. This is relevant for discovering
energy loss in the upcoming oxygen-oxygen (OO) run at the LHC, for which a
reference pp run is currently not planned. For hadrons and jets we compute the
ratio of spectra between different pp collision energies in perturbative QCD,
which can be used to construct a reference spectrum. Alternatively, it can be
interpolated from measured spectra at nearby energies. We estimate the
precision of both strategies for the spectra ratio relevant to the oxygen run,
and conclude that the central values agree to 4% accuracy for hadrons and 2%
accuracy for jets. Finally we propose taking the ratio of OO and pp spectra at
different collision energies, which cleanly separates the experimental
measurement and theoretical computation.
