The application of natural and analogue signals to variety analysis require an estimate of Ashby's "powers of discrimination" (see above quote). Given the butterfly effect of dynamical systems care must be taken before quantitative measures can be produced. Small quantities, which might be overlooked, can have big effects. In his "Designing Freedom" Stafford Beer discusses the patient in a hospital with a temperature denoting fever. Action must be taken immediately to isolate the patient. Here no amount of variety recording the "patients' average temperature" would detect this small signal which might have a big effect. Monitoring is required on individuals thus amplifying variety (see "Algedonic alerts" in the viable system model or VSM). Beer's work in management cybernetics and VSM is largely based on variety engineering.