  A variation of the Scott analysis of countable structures is applied to
actions of non-Archimedean TSI Polish groups acting continuously on a Polish
spaces. We give results on the potential Borel complexity spectrum of such
groups, and define orbit equivalence relations that are universal for each
Borel complexity class. We also identify an obstruction to classifiability by
actions of such groups, namely generic ergodicity with respect to $E_\infty$,
which we apply to Clemens-Coskey jumps of countable Borel equivalence
relations. Finally, we characterize the equivalence relations that are both
Borel-reducible to $=^+$ and classifiable by non-Archimedean TSI Polish groups,
extending a result of Ding and Gao. In the process, several tools are developed
in the Borel reducibility theory of orbit equivalence relations which are
likely to be of independent interest.
