Dispersal to a greater degree than usual, expected, or desirable; greater sparseness, separateness, or regularity of distribution than would be predicted to arise randomly.
Origin
1950s; earliest use found in Journal of Animal Ecology. From over- + dispersal.
Definition of overdispersal in US English:
overdispersal
nounˌəʊvədɪˈspəːsl
Dispersal to a greater degree than usual, expected, or desirable; greater sparseness, separateness, or regularity of distribution than would be predicted to arise randomly.
Origin
1950s; earliest use found in Journal of Animal Ecology. From over- + dispersal.