Most people who use the enumerate environment to produce a
syllabus or other long nested lists of short items are dismayed
by the amount of space between the items. The outline
environment, which is essentially the same as enumerate,
suppresses some of this space. It leaves space, however, at the
beginning and end of a list, but not a sublist. For example
You should use the outline environment sparingly. For
most purposes, even for a list of a few short items, the enumerate environment produces more pleasing results.