Your goal, which you didn’t state, has some bearing on what is the more effective way to reach that goal. I’m partial to listening for a while, but eventually one has to start using the language.
But there’s the Benny Lewis “speak from day one” approach, which I would think gets one communicating sooner, but not necessarily with good grammar, vocabulary, or pronunciation. (And if you read much of Lewis, it becomes apparent that “day one” isn’t really day one—he learns some in advance from phrase books.
Another interesting thing about methods is expressed in one of my favorite quotes:
“In the field of language teaching, Method A is the logical
contradiction of Method B: if the assumptions from which A claims
to be derived are correct, then B cannot work, and vice versa. Yet
one colleague is getting excellent results with A and another is
getting comparable results with B. How is this possible?”
— Earl W. Stevick
I can’t easily cite the studies I’ve read, but things I’ve heard or witnessed are in one of my comments on another answer. I think one answer to Stevick’s rhetorical question is that people are different. One method might do wonders for a third of the people; another do wonders for another third. And the salesmen/evangelists tell you all about their model third, not mentioning the ones that are disappointed.
In my own experience, after years of getting top grades in Spanish, I went to Guadalajara and found that I could not communicate. Some will gloat that this proves only comprehensible input works. But I think that all that grammar and vocabulary made all the input comprehensible, allowing me to speak well within two weeks.