"Three times smaller" makes no sense to me

I was reading an article this week about an early hominid, and the description of the skull indicated that the creature's brain would have been "three times smaller" than that of a modern human.

It's a commonly used phrase (800K Google hits), and I know what the author meant.  He/she was saying that the brain was "one-third the size of a modern human brain."  But to me "three times smaller" is a dreadful construction because it could just as well mean "one-fourth the size" ("two times smaller" would be one-third the size, and "one times smaller" would be half-size).