The term checklist can be defined quite broadly depending on usage and circumstances. However, in general terms, checklist refers to a detailed list of items that have been grouped together for one of a few purposes. First, it helps to assure that none of the items on the checklist are inadvertently forgotten or otherwise overlooked. With everything in one convenient, handy place, it is far easier to assure that all items are properly attended to. Secondly, grouping of items in such a way helps to provide for easier comparative assessments. It is a good idea to develop a checklist at the very onset of a project as it assures from the very beginning that all relevant tasks and activities are itemized in one central location throughout the life of the project. As the project advances, individual items may be checked or crossed off to indicate completion, and in addition, depending on level of detail required, dates of completion may be included. Additionally, checklists can be developed for individual schedule events within the project, although they should work in conjunction with the overall project checklist.
This term is defined in the 3rd edition of the PMBOK but not in the 4th.