[ExI] Black Swan event.

[BillK]

On Wed, 12 Jun 2019 at 04:34, Keith Henson <hkeithhenson at gmail.com> wrote:
>
> https://en.wikipedia.org/wiki/Black_swan_event
>
> The event results may be terrible, but that's not part of the definition.
>
> Based on the author's criteria:
>
> "The event is a surprise (to the observer).
> The event has a major effect.
> After the first recorded instance of the event, it is rationalized by
> hindsight, as if it could have been expected; that is, the relevant
> data were available but unaccounted for in risk mitigation programs.
> The same is true for the personal perception by individuals."
>
> It would be kind of interesting to list events unexpected enough to be
> called black swan events.
>


I don't think you can do that.  :)
Black swan events are rare and thought to be impossible (until they
actually happen).
Although, - Why, sometimes I've believed as many as six impossible
things before breakfast. ― Lewis Carroll

Perhaps Grey Swan events would cover that situation.
Nomura's Bilal Hafeez writes, while he would like to be able to
predict black swans, by definition that is impossible. "However, its
close cousin the grey swan can be foreseen. These are the unlikely but
impactful events that, in our opinion, lie outside the usual base case
and risk scenarios of the analyst community.
------------------------

For example, hurricanes are not Black Swan events - they are not unexpected.
But an especially severe hurricane that maybe effectively wiped out a
city would be a Grey Swan.

BillK