We propose a model-independent quantity, $L/G$, to characterize non-Gaussian tails in beam profiles observed with the Fermilab Booster Ion Profile Monitor. This quantity can be considered a measure of beam halo in the Booster. We use beam dynamics and detector simulations to demonstrate that $L/G$ is superior to kurtosis as an experimental measurement of beam halo when realistic beam shapes, detector effects and uncertainties are taken into account. We include the rationale and method of calculation for $L/G$ in addition to results of the experimental studies in the Booster where we show that $L/G$ is a useful halo discriminator.