Severe: recovery requires some time and more complex corrective measures. Critic: exceeds the tolerable threshold and is not recoverable regardless of the corrective measures (this is the type of impacts that, in theory at least, make a project viable and stopped). It is difficult to determine the difference between severe and critical, especially because be recoverable or not by corrective measures depends on the budget which is handled. When evaluating different methodologies are used: a. direct prosecution. b.

qualitative aspects. Simple criteria on non-quantifiable characteristics and that they can be better defined using classes. c. quantitative systems: or partial: application of models, types. or global: specific models for specific actions are performed. Ex: Batelle Columbus method.

The severity of an impact will come determined by its magnitude (in terms of its intensity and extent) characteristics. We must transform this into an approximate mode value.