Almost every time I read advice about writing, the person giving the advice insists that a good writer needs an outline for the entire novel before they begin. It does make sense because an outline will keep the story flowing in the right direction. It can also keep the writer from wandering off in directions which aren't important to the story. For those reasons, I do write outlines for my novels, but I'll never insist everyone has to follow my lead.
     Outlines often grow and change through the course of writing a novel. No matter how detailed an outline might be, notes can be added when some action in an early chapter needs to be addressed at some later time. In my case, I'll create a piece of evidence and then note in my outline when that evidence is revealed as an important clue or will be used during the course of an interrogation. Outlines can and will keep things moving in a logical direction. Another reason outlines change after the writing begins is because the characters take on a life of their own. I've written more about that on my page titled "Characters live".
     I start with a very simple outline and add more details under each section as I write. I'll list "interrogate suspect" where that will occur. When I get to that point, I'll add more details about the conversations and actions. I might have a note such as "talk to Clarissa at supper about [topic here]" with some of the details about the conversation. When I get to that point, I might decide that would be more of surprise to to readers if I wait until a few chapters later and I can relocate the entire block of information to another part of the outline. Because I'm writing a series, I've come across a few things in an outline that I removed entirely from that book and added to the next one.
     The bad part about relying on an outline has to do with the flow of the plot. Some writers will create an outline and stick to it no matter how far they wander from the main action of the story. Any and all subplots can sound as if they add some excitement to the story until writing actually begins. Unless a star pitcher on the baseball team wants to lose, he won't be thinking about his date with his girlfriend during the college championship game. If you plan to strictly follow an outline, make sure it makes sense before deciding its ready.