I have a very serious question and one that I have never found a true “answer” to. When you are writing dialogue between two characters do you write…

“What are you doing, “Jack said.

or do you write…..

“What are you doing,” said Jack.

I have always written the name before said, and I am starting to wonder if it really makes a difference. Is there a reason to put one first, or second in that tag of dialogue? Or is it merely preference at the end of the day?