The Phi-measure of event-by-event fluctuations in high-energy heavy-ion col
lisions corresponds to the second moment of the fluctuating quantity distri
bution of interest. It is shown that the measure based on the third moment
preserves the properties of Phi but those related to the higher moments do
not. In particular, only the second and third moment measures are intensive
as thermodynamic quantities. The Phi(2)- and Phi(3)-measure of p(perpendic
ular to)-fluctuations are computed for the hadron gas in equilibrium and th
e results are analyzed in context of the experimental data. (C) 1999 Publis
hed by Elsevier Science B.V, All rights reserved.