Uncertainty refers to the subjective experience of having insufficient information about a problem of interest.(1;2) A person may be able to reduce uncertainty by collecting informative data. However, often information does not exist in the human domain (question has not been researched) or is not available (not published or not retrievable) – epistemic uncertainty (ignorance).(3) Uncertainty is due to a lack of information – we „don‘t know“! In addition, uncertainty may result from the structure of the environment itself (large number of relevant factors [complexity] or probabilistic nature of the phenomenon of interest) – aleatoric uncertainty (ambiguity).(3) In the latter case, uncertainty is confirmed by the data, i.e. “we are certain to be uncertain”, and uncertainty cannot be reduced by learning. All these sources are relevant for medical diagnosis, prognosis, treatment and prevention. read more