Normality and sanity

I am still reading Aid on the Edge of Chaos. The book is divided in three parts: the first one describes how international aid works; the second one explains complexity ideas, covering concepts such as networks and power-law distributions; and the third one applies ideas of complexity to international aid. 

Power-law distributions are interesting--this kind of distribution is an initial indicator that a phenomenon is complex. The basic concept is that some variables do not have a normal distribution, instead very few observations are extreme and have low frequency, most observations are not extreme--the distribution of earthquakes is one example. The distribution of homicides in the world (see figure 1 here) by country, and also of malnutrition, seem to have a power-law distribution, which means that there are many feedback effects between these variables and others--there is a lot going on behind the distribution. 

To be sure, just the fact that a variable has a power-law distribution does not mean that it is complex. 

The author writes:

Perhaps clinging to the mast of normality is the only way to stay sane in a world of extremes and outliers. But it also means we are consigned to treating the irregular and extremes as continuous shocks. p. 219.