The width (top) and effective $p_{\rm T}/m$ (bottom) fit parameters as a function of the mean number of participants in pp, p$-$Pb, and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. Vertical uncertainties are the standard error on the best-fit parameter values, while horizontal uncertainties reflect the uncertainty on $\langle\N_{\rm part}\rangle$ from the Glauber calculations. Also shown are similar fit parameters from the same parameterisation of EPOS-LHC calculations as well as direct calculations of the standard deviation of the ${\rm d}N_{\rm ch}/{\rm d}y$ distributions and the $\langle p_{\rm T} \rangle / \langle m \rangle$ ratio from the EPOS-LHC calculations.