Activity Vs Task
Is it schedule activities or schedule task? Depending on the software or names of the fields, both are right. Now comes along Lean Construction and it has defined tasks as part of the Last Planner System and even goes so far as calling the wall boards for planning 'Task' Boards. So which is it? Are both correct and how do we discern between each so as not to confuse our audience or participants in the planning process?
Activities
Lets start by defining the Activities. In PMI's PMBOK, within the Schedule Management Knowledge area, there is a process called Define Activities. From the WBS / Work packages, "Activities" focus on the work that needs to be done in order to complete the work packages. Additionally, the Activities should contain attributes such as activity codes, activity description, predecessor activities, successor activities, logical relationships, leads and lags, resource requirements, imposed dates, constraints and assumptions. The Activities should contain enough detail information to enable the team to perform the work described; and measure the work's performance. These are what eventual become the CPM network for the project schedule. There are some general rules in terms of duration in that the activities should not span more than one update cycle for the work that is acted upon or scheduled to be work (i.e. 2 week update period = 10 Working days). In cases when Rolling Wave Planning is adopted, teams argue that not enough information is available in order to comply with this rule and therefore activities will span a much longer duration; until such time more detailed activity information is available and further breakdown can occur.
Tasks are defined in the same manner depending on who you talk to, what software you use or even the planning method used. For instance, Oracle Primavera P6 calls the lowest level of a WBS a "work package" and the items that describe the work to be done as "Activities". MS Project refers to them as "Tasks" as does Agile Planning Methods. Finally, the Oracle Prime Projects uniquely has "Activities" and "Tasks" in a single solution. The confusion this article wishes to address is the distinction of "Tasks" in the Lean Construction Institute's Last Planner System vs "Activities" in the CPM.
Lean Planning
So is there a clear distinction between an Activity and a Task? Most forums would say no, but when using Lean Construction method, you will need to segregate the two for the purposes of discussions, Pull Planning and Last Planner commitments. Using this methodology, Activities refer to the items list within the Critical Path Method (CPM) schedule estimated by the Project Manager, Scheduler or Superintendent; whereas Tasks are related to the items on the planning board that individual Last Planners estimate and commit to.
Prime Lean Scheduling
Most people would say, "so what, CPM and the Last Planner System are separate".
Well not anymore, with the appearance of Oracle Prime Projects in the project management software realm, both of these systems work together in a single program.
Prime Lean Scheduling, as it is referred to, combines both CPM and Lean into a common digital platform. Now there is a true distinction between the two nouns, and within the software the two areas are only divided by the applications Schedule and Tasks. The Task Planning Board is now replaced with a digital planner which allows the team members to 'place' their Task and commit to them with ease. The Task are in turn tied to the CPM Activities which are the drivers of the project schedule.
Summary
Tasks, activities, stuff to do, call it what you will. All can be used to define work to be accomplished in a project. What ever you call them, as long as you are doing your due diligence in proper pre-planning, or execution planning, you are on track to success in Project Management
