Event rates are calculated by using a Monte~Carlo technique taking into account of the neutrino flux, the #tex2html_wrap_inline520# cross-section~[#botts##1#] and the muon propagation in the matter surrounding the detector. The uncertainties on quoted number depend on the uncertainties on these parameters. The most relevant parameter for the error propagation is the #tex2html_wrap_inline522# cross-section which is now well constrained at energies below 100TeV but becomes badly known for energies far above 100TeV.
No error estimate are reported on the predicted fluxes given by different authors for extra-galactic sources. For atmospheric neutrinos an uncertainty of about 20 is likely.
Therefore an overall uncertainty of the order of 30 is expected on the predicted sensitivities to galactic sources and an overall uncertainty of one order of magnitude may be estimated on predicted event rates for extra-galactic sources.