  We analyze the efficiency of different methods for the calculation of
reaction rates in the case of two simple analytical benchmark systems. Two
classes of methods are considered: the first are based on the free energy
calculation along a reaction coordinate and the calculation of the transmission
coefficient, the second on the sampling of dynamical pathways. We give scaling
rules for how this efficiency depends on barrier height and width, and we hand
out simple optimization rules for the method-specific parameters. We show that
the path sampling methods, using the transition interface sampling technique,
become exceedingly more efficient than the others when the reaction coordinate
is not the optimal one.
