Left: Nuclear modification factors measured by ALICE in central (0--5\%) and peripheral (70--80\%) Pb--Pb collisions and in p--Pb collisions at $\snn = 5.02$ TeV. Right: A comparison of the nuclear modification factors for central (0-5\%) Pb--Pb and p--Pb collisions measured by ALICE and CMS . In both figures, the \pt-dependent systematic uncertainties are shown as boxes around data points. The normalization uncertainties are shown as boxes around unity.