"Dragon-kings: Mechanisms, statistical
methods and empirical evidence
D. Sornette and G. Ouillon
This introductory article presents the special Discussion and
Debate volume “From black swans to dragon-kings, is there life beyond
We summarize and put in perspective the contributions
into three main themes: (i) mechanisms for dragon-kings, (ii) detection
of dragon-kings and statistical tests and (iii) empirical evidence in a
large variety of natural and social systems.
Overall, we are pleased to
witness signiﬁcant advances both in the introduction and clariﬁcation
of underlying mechanisms and in the development of novel eﬃcient
tests that demonstrate clear evidence for the presence of dragon-kings
in many systems.
However, this positive view should be balanced by the
fact that this remains a very delicate and diﬃcult ﬁeld, if only due to
the scarcity of data as well as the extraordinary important implications
with respect to hazard assessment, risk control and predictability."