As you construct a comparison, you can often avoid wordiness by shortening the basis of the comparison. However, doing so can introduce ambiguity, so abbreviate your bases of comparison with care. If you shorten your basis of comparison, you must check to make sure that the basis is still clear.
You can often repair an ambiguous comparison by adding a pronoun.
The symposium revealed that more was known than
realized.
[More was known than was accomplished, or more was known than was thought?]
The symposium revealed that more was known than we
realized.
--Norman Boucher, "Back to the Everglades," Technology Review (modified)
You can often repair ambiguous comparisons by adding an auxiliary verb.
Von Neumann took a very different approach towards artificial intelligence
(AI) than other computer scientists.
[Was his approach toward AI different from his approach toward other computer
scientists, or was his approach different from the approach of other computer
scientists?]
Von Neumann took a very different approach towards artificial intelligence
(AI) than other computer scientists did.
--Kai Wu, "Artificial Life," SciTech Magazine (modified)