David Allen describes the difference between what you’ll find on a next action list and a to do list:
90+ % of the to do lists I’ve seen are incomplete inventories of still-unclear things. The Next Action definition (if you’re really getting down to having no ambiguity about the next visible physical activity required to move something forward), actually finishes the thinking you’ve implicitly agreed with yourself that you’ll do. “Mom” is an unclarified to do item. But when “Mom” is translated into “Celebrate Mom’s birthday with a party” as a project outcome, then “Call Sis about what we should do for Mom’s birthday” is a clear next action. Because “Mom” is vague, it still triggers stress when you look at it on a list. “Call Sis . . . ” triggers action and positive engagement.