For a long time, I was unsure of the correct way to finish this sentence: Helen is shorter than . . . Shorter than me or shorter than I?
The proper term for this construction is an elliptical clause. That’s a grammarian’s way to say, “Finish the sentence to get the meaning.” Technically, it means that some words are left out because they’re understood.
In the sentence above, complete the thought: Helen is shorter than me am short or Helen is shorter than I am short. If you do that, you'll see that the obvious answer is Helen is shorter than I.