Things to check before hiring an Expert Witness or Consultant include:

▪ Does the appraiser have expert witness experience?
▪ What professional designations does the appraiser hold?
▪ Has the appraiser received continuing education, particularly in the area 
  needed?
▪ How long has the appraiser been performing valuations?
▪ Has the appraiser published articles, taught classes, and lectured on appraisal
  topics?
▪ Are good references readily available for the appraiser?

An appraiser also may work as a consultant to assist with such things as:

▪ Reviewing the valuation clause in a buy-sell agreement.
▪ Review of other expert's work.
▪ Interpreting a company's financial statements and other information.
▪ Exploring the strengths and weaknesses of both sides of the case from a
  valuation perspective.
▪ Determining which discovery documents may be useful or necessary for
  analysis.
▪ Developing questions to ask opposing experts or principals regarding
  valuation facts and issues.

 As a consultant, a valuation professional is free to act as an advocate for the attorney and the client.  In an appraiser and expert witness role, the appraiser must not be an advocate for either side.