Observations and N -body simulations both support a simple relation for the disruption time of a cluster as a function of its mass of the form : t _ { dis } = t _ { 4 } \times ( M / 10 ^ { 4 } M _ { \odot } ) ^ { \gamma } .
The scaling factor t _ { 4 } seems to depend strongly on the environment .
Predictions and observations show that \gamma \simeq 0.64 \pm 0.06 .
Assuming that t _ { dis } \propto M ^ { 0.64 } is caused by evaporation and shocking implies a relation between the radius and the mass of a cluster of the form : r _ { h } \propto M ^ { 0.07 } , which has been observed in a few galaxies .
The suggested relation for the disruption time implies that the lower mass end of the cluster initial mass function will be disrupted faster than the higher mass end , which is needed to evolve a young power law shaped mass function into the log-normal mass function of old ( globular ) clusters .