A decision is made, or a decision event occurs, when
the decision-maker (generally a single individual) surveys a known and
fixed set of alternatives, weighs the likely consequences of choosing
each, and makes a choice. [In an ideal situation], the
decision maker evaluates the options in terms of a set
of goals, purposes, or values that are stable over time,
and that he or she knows quite clearly (Klein, Orasanu,
Calderwook and Zsambok, 1993: 5).