What type of uncertainty is robustness referring to in Information Gap Decision Theory?

Summary, in English

In Information Gap Decision Theory (IGDT) a system is said to be robust to uncertainty if specified goals are achieved with satisfaction despite large info-gaps. Under this theory an info-gap expresses the disparity between what is known and unknown in structures for which uncertainty is judged as severe. We discuss how robustness in IGDT can be merged with a perspective on risk which allows for descriptions and characterisations of risk on the basis of broad uncertainty assessments. Robustness in IGDT is found to be related to a combination of a measure of uncertainty in consequences of a decision and a judgement of strength in knowledge underlying the quantification of this uncertainty. Thus an info-gap is a way to quantify a type of second order uncertainty. We suggest that it would be possible to view the “level of uncertainty” α in the info-gap model as the decision maker’s “level of sensitivity to strength in knowledge”. Robustness (Formula presented.) is then describing how sensitive the assessor can be to strength in knowledge and still be confident that this is an acceptable decision.