Kinnard et al (2002) note that there are 50 different court systems in the US and stated that one of the objectives of future changes to the Uniform Standards of Professional Appraisal Practice (USPAP) should result in a credible methodology that courts could rely on for objective brownfield valuations. The approach by appraisers was characterized as “typically simplistic”, with most value estimates underpinned by limited market data and quantitative analysis. Kinnard et al found that few appraisers considered the published literature important in solving the brownfield valuation problem and noted that guidelines from professional societies offer little beyond admonitions to perform competently, acquire technical assistance and expertise from others where necessary, and report fully what they did. These are reasons for malpractice litigation; the the only likely solution.
Kinnard et al discussed a March, 2000 task group that was formed to improve the USPAP with an objective “to insure that any application of statistical or market survey technique to the appraisal of real property is in conformance with the requirements of the modifications to rule 702 (Federal Rules of Evidence)". This was an attempt to obtain some consistency and standards in application so that the results will be acceptable as evidence of value in court. The courts would decide the acceptability of the methods used for identifying and measuring the impact of environmental risks and stigma on market value.
Crosby et al. (1998) cited in Bretten and Wyatt (2000) examined 38 court cases in the UK in an attempt to find reasons for wide variances in valuations of non-contaminated real estate. They provided three reasons for the wide range value estimates that in the courtroom:
Expert witnesses are unfit to present themselves as "experts"
The margin of error considered acceptable is inappropriate and should be increased
Expert witnesses have been influenced to produce certain valuations to suit their client's particular needs
Crosby et al (1998) found judges sometimes arbitrarily agree with one valuer, and that:
the entire process is arbitrary
it lacks any empirical basis, and
it is fundamentally flawed.