The possibility should be considered that the underlying distribution of the data is not approximately normal, having "fat tails".
Most models try to model the hazard rate by choosing the underlying distribution depending on the shape of the hazard function.
The former definition may not be a coherent risk measure in general, however it is coherent if the underlying distribution is continuous.
The properties listed so far are all valid regardless of the underlying distribution of the error terms.
In order to make any use of unlabeled data, we must assume some structure to the underlying distribution of data.
If one has knowledge of the underlying distribution of the data, this may indicate using one of the other choices.
It underpins the concept of the canonical ensemble, providing the underlying distribution.
Its calculation does not require any knowledge of the form of the underlying distribution - hence the name nonparametric.
If the underlying distribution is symmetrical γ itself is asymptotically normal.
An interesting question is how well the order statistics perform as estimators of the quantiles of the underlying distribution.