ASAP, ALAP and ATAP are acronyms that stand for, respectively, as soon as possible, as late as possible and as timely as possible.
The acronyms ASAP and ALAP are frequently heard in relation to scheduling and project management but are also widely used in other business-related and non-business contexts. Starting a task as soon as possible is usually considered the best approach. In practice, however, starting a task as soon as it can possibly be done and, conversely, leaving it as long as possible can both have problems associated with them.
If a task is begun as soon as it can be, for example, there may be information yet to come that impacts its successful completion. To avoid that issue and other potential problems, ALAP scheduling is sometimes advocated. However, if a task is left as late as possible, unforeseeable events can occur that make the task take longer than anticipated, resulting in missed deadlines.
To avoid such difficulties, many scheduling experts advise analyzing tasks on a case-by-case basis to decide when the most opportune time is to begin, an approach sometimes called as timely as possible.