State Variation in Certain Rules Governing Expert Witness Testimony

States differ by statute in the degree to which they follow aspects contained in four federal rules governing expert witness testimony. Where departures exist, they tend to occur in patterns involving two or more states. The variation across states and the District of Columbia are catalogued as of July 2016 and presented in tabular form. The tables show (a) where there is state adherence to one or more of the federal rules surveyed; (b) the most common departure from each of the federal rules examined; (c) less common departures from the federal rules examined; and (d) a state-by-state listing with the various departures identified for each state.