Reading Philip Ball's "Critical Mass" book one gets a deep understanding of how things are related. As the subtitle of the book implies -how one thing leads to another. We have used mathematical approaches to establish a language (framework) to relate cause and effect as well as, in many acceding, the path in which the process is carried out.
For a statistical analysis to be strong and confiable is it necessary to have a good set of information, data in sufficient quantity that allows us to see the pattern that describes the system in question. This sufficiency in the amount of information is what we call "critical mass" a term borrowed from nuclear physicist that define the critical mass of a nuclear reaction in terms of the density of radionuclides involved in the reaction. All in nature including of course human behaviour requieres a critical point from which reference is made. A city or town doesn't becomes a city or town until that critical mass is acquiered