I can do outlines for lengthy scenes, but not usually for an entire novel. It's more a case that I have certain things that I want to include and then check them off as I go along. Other times, entire scenes will play out in my head (usually when I'm in the bath/on a walk and can't write them down) so I scribble them down as is and then work them in later.
Outlines may help me see where I want to get to in the end, but since I tend to start off with a single idea/scene and then work forward from there, I don't often know exactly how the story will end before I get to the half-way point. Or if I have an idea for an ending, by the time I get there, I may think that's terrible and want to try something else entirely. (Even if it means cutting out a character completely.)
Basically, outlines are great for essays. For anything where the content is likely to be much more fluid, it's probably best not to plan too rigidly.