  Effect of energetic disorder on charge carrier transport in organic materials
has been reexamined. A reliable method for mobility calculation and subsequent
evaluation of relevant disorder parameters has been discussed. This method is
well suited for a direct calculation of the magnitude of dipolar disorder
$\sigma_\textrm{dip}$ in polar organic materials from the current transients.
Calculation of $\sigma_\textrm{dip}$ for several transport materials with
varying concentration of polar dopants gives concentration dependences that are
in reasonable agreement with theoretical predictions. A possible solution of
the puzzle concerning the disorder effect on the mobility temperature
dependence has been suggested.
