"better than me" vs "better than I do"

Question

From English grammar point of view, which of below sentence is correct? And why?

He did this better than I did.

He did this better than me.

Answer 1

Both are correct.

The subject in these sentence is "he", and there is only one subject. "Better than" is a proposition that is followed by an object. The pronouns used as objects are me, you, him, her, us, and them.

Compare to "he is taller than me", "I am smarter than him", "they are like us".

The object can also be a clause, which is a mini-sentence that has a subject of its own, like "I run faster than I walk". Here the first "I" is the subject of the sentence, and the second is part of an object clause, in which it is the subject. The second "I" is not an object, so you won't say "me walks".

See also:

http://www.oxforddictionaries.com/words/i-or-me

http://m.wikihow.com/Choose-Between-%22I%22-and-%22Me%22-Correctly

http://www.elearnenglishlanguage.com/blog/english-mistakes/i-vs-me/