A Review of Damage Intensity Scales

A wide range of scales and indices are used to describe natural hazards and theirimpacts. Some scales infer damage levels from hazard characteristics while othersuse damage levels to estimate a physical characteristic. Damage scales may relyon raw dollar values, percent loss estimates, damage states, normalized values ormacrodamage categories. Whatever the basis of the scale it should tell the truth.However, scales are compromises between the need for detailed information andbeing simple enough to use.Damage scales may be nominal (categorical), ordinal, interval or ratio scales. Frequencywords such as ``few', ``many' can be dealt with in a range of ways to produce contiguous,widely separated, broadly overlapping or narrow overlapping values. Most scales rely onmaximum values but some focus on minimum or threshold values. The number of levelson damage scales commonly ranges from five to 13. Some long-lived damage scales haveevolved through several editions, changing to reflect the new or additional uses to whichthey have been put and as buildings and the nature of damage to those structures has changed.Few scales state precisely the purpose of the scale, deal clearly with ambiguities or provideguidelines for the use of qualitative information.