▁analysis ▁and ▁conclus ions ▁and ▁share ▁the ▁report ▁with ▁all ▁other ▁parties . ▁This ▁allows ▁other ▁parties ▁to ▁effectively ▁cross - ex am ine ▁the ▁expert . ▁ ▁Types ▁of ▁expert ▁witness ▁ ▁Test ifying ▁exper ts ▁If ▁the ▁witness ▁needs ▁to ▁test ify ▁in ▁court , ▁the ▁privile ge ▁is ▁no ▁longer ▁protected . ▁The ▁expert ▁witness ' s ▁identity ▁and ▁nearly ▁all ▁documents ▁used ▁to ▁prepare ▁the ▁testim ony ▁will ▁become ▁discover able . ▁Usually ▁an ▁experienced ▁lawyer ▁will ▁advise ▁the ▁expert ▁not ▁to ▁take ▁notes ▁on ▁documents ▁because ▁all ▁of ▁the ▁notes ▁will ▁be ▁available ▁to ▁the ▁other ▁party . ▁ ▁An ▁expert ▁test ifying ▁in ▁a ▁United ▁States ▁federal ▁court ▁must ▁satisfy ▁the ▁requirements ▁of ▁Fed . ▁R . ▁Ev id . ▁ 7 0 2 . ▁Gener ally , ▁under ▁Rule ▁ 7 0 2 , ▁an ▁expert ▁is ▁a ▁person ▁with ▁" s cient ific , ▁technical , ▁or ▁other ▁special ized ▁knowledge " ▁who ▁can ▁" ass ist ▁the ▁tri er ▁of ▁fact ," ▁which ▁is ▁typically ▁a ▁j ury . ▁A ▁witness ▁who ▁is ▁being ▁offered ▁as ▁an ▁expert ▁must ▁first ▁establish ▁his ▁or ▁her ▁compet ency ▁in ▁the ▁relevant ▁field ▁through ▁an ▁exam ination ▁of ▁his ▁or ▁her ▁credentials . ▁The ▁oppos ing ▁att orney ▁is ▁permitted ▁to ▁conduct ▁a ▁voir ▁dire ▁of ▁the ▁witness ▁in ▁order ▁to ▁challenge ▁that ▁witness ’ ▁qual ifications . ▁If ▁qualified ▁by ▁the ▁court , ▁then ▁the ▁expert ▁may ▁test ify ▁" in ▁the ▁form ▁of ▁an ▁opinion