Research conducted by an independent firm and used to support arguments before the US Patent and Trademark Office or civil courts when trying to prove various aspects of trademark viability. For example, a survey may be useful to prove that a mark has acquired secondary meaning, is not generic, is not functional, is legally strong, or is not likely to confuse consumers with regard to an existing trademark. Surveys can also be used to prove plaintiff's lost profits, which is evidence that is notoriously difficult to obtain without a survey. According to Phyllis J. Welter, an expert on trademark surveys, the discussion of surveys in trademark litigation has grown from roughly 5.6% in the 1950's to over 12% in the 1980's. Ms. Welter's book, Trademark Surveys, published in 1998 by West Group, is an excellent source of information on how to utilize surveys in trademark litigation.