In appraisal, an extraordinary assumption relies on what key characteristic?

An extraordinary assumption in appraisal refers to a condition or fact that is assumed to be true for the purpose of the analysis, even though it may not be supported by direct evidence. The key characteristic of this type of assumption is that there must be some support by evidence, albeit not necessarily conclusive. This support can come from various sources, such as market data, historical trends, or expert opinions, that suggest that the assumption is reasonable and plausible for the purpose of the appraisal.

Using extraordinary assumptions allows the appraiser to proceed with the analysis when certain facts are unknown or cannot be verified at the time of the appraisal, while still grounding their work in evidence that provides a level of credibility to these assumptions. This practice is critical to maintaining the integrity of the appraisal process and helps ensure that conclusions drawn are based on sound reasoning instead of conjecture.