To identify methodological categories, the outcome
of each
paper was
classified according to a set
of binary variables: 1 - outcome measured on biological material; 2 - outcome measured on human material; 3 - outcome exclusively behavioural (measures
of behaviours and interactions between individuals, which in studies on people included surveys, interviews and social and economic data); 4 - outcome exclusively non-behavioural (physical, chemical and other measurable parameters including weight, height, death, presence / absence,
number of individuals, etc...).
Bringing together a sound sculpture and a
number of works on
paper, KH - 21 makes reference to the recently declassified HEXAGON Program
of the United States» National Reconnaissance Office which launched 20 highly
classified intelligence gathering satellites between 1971 - 86.