Obviously the random component precedes the non-random one in the causal chain.
Such a modelling approach is not without its critics, particularly on the grounds of insufficient data, uncertainty and the non-random distribution of weeds.
Migration is non-random and is associated with deprivation.
One of the strongest non-random patterns is that rich and powerful people are healthier than poor and powerless people.
We opted instead for a non-random sample from different contexts in order to capture a more diverse pool of respondents.