  We investigate, in a set of 3D numerical simulations of driven, magnetized,
isothermal, and self-gravitating molecular clouds (MCs), the statistical
correlations between the energy ratios (thermal/gravity, and kinetic/gravity)
of clumps and cores (CCs) identified in the simulations and gravitational
binding indicators commonly used in observational studies such as the Jeans
number, J_{c}, and the virial parameter, alpha_{vir}. In the energy ratios, we
consider the surface energy terms which account for the effects of the
environment on the clump gravitational boundedness. We find that: a) J_{c} and
the thermal/gravitational energy ratios are well correlated, b) alpha_{vir} and
the (thermal+kinetic)/gravity or kinetic/gravity energy ratios are poorly
correlated, additionally affected by the ambiguity of the compressive or
dispersive effect of the velocity field. This result suggest that the use of
alpha_{vir} estimates in the observations is only useful to assess the
kinetic+thermal energy content of a CC and not its gravitational boundedness.
Finally, we discuss briefly the possibility of measuring the kinetic energy
surface term directly in the observations.
