The Inside Write Stuff: simplify subordinate clauses that include a “to be” verb

(1) Although they were used in the 1990’s, derivatives since then have become much more sophisticated and common.

(2) Although used in the 1990’s, derivatives since then have become much more sophisticated and common.

Variation 1 is wordy; the second variation has stylish brevity. When you see is, are, was, or were in a subordinate clause, seize the opportunity to eliminate them and streamline your writing.