  We discuss an event-by-event fluctuation analysis of particle production in
heavy ion collisions. We compare different approaches to the evaluation of the
event-by-event dynamical fluctuations in quantities defined on groups of
particles, such quantities as mean transverse momentum, transverse momentum
spectra slope, strength of anisotropic flow, etc.. The direct computation of
the dynamical fluctuations and the sub-event method are discussed in more
detail. We also show how the fluctuation in different variables can be related
to each other.
