Why does RAMAS Red List assign the widest possible range to parameters that are left blank?
A. This issue was discussed at an IUCN workshop on uncertainty in Sydney, Australia, in May 1999. The participants felt that it was more precautionary to assume a blank parameter meant “unknown” rather than “ignored”. When a parameter is “ignored”, the program assumes that the criteria that refer to that parameter are not met. This is the same as “skipping over” or “omitting” a criterion. However, when a parameter is specified as “unknown”, the program sets it to the widest possible range. This is both more precautionary and consistent. The alternative of ignoring or omitting a criterion when data are lacking is inconsistent for the following reason. Suppose there is no data on population size, and thus Criterion D is omitted. Suppose the assessment then is least concern (LC). Then, more data are collected, and it is realized that 500-5000 is a realistic range for the population size. When these data are entered, the assessment covers the range from VU to LC. Thus, the assessment becom
