boeinz
Which one is correct?
1. My child has better hygiene than my sister's child.
2. My child has better hygiene than that of my sister's child.
I think this is a parallelism issue more than anything. #1 sounds better to me, because "my child" is the subject of the sentence and you're comparing "my sister's child" to " my child", which makes sense.
In #2, you're comparing "my child" to the hygiene of that of my sister's child, so this doesn't make sense. Not sure if this is the right answer, but that's how I rationalize it from a more or less intuitive POV. Any other takers?