Glenn Ballard's Last Planner
The Last Planner
by Glenn Ballard
The Last Planner presents a new management technique for production planning of construction work. Its consistent application has:
(1) proven to lead to dramatic labor productivity gains,
(2) aided in making the flow of work downstream from The Last Planner more reliable,
(3) increased throughput by reducing the need for buffers and therefore reducing the effort spent on re-handling and keeping track of materials on site, and
(4) freed up worker time and energy to improve work methods.
Construction planning at the field level is done by foremen or superintendents. They commonly use 3- or 4-week lookahead schedules in which they itemize and sequence work for the crew to perform; spell out who will do what; and specify which area to work in, materials to install, and equipment to use. In addition, they may create weekly work plans, which are one-week lookahead schedules that show the next week's assignments. Studies by Ballard and Howell have shown that weekly work plans have low reliability, that is, many--in fact most!--of the planned activities end up not being completed by the end of the week. Failure to complete planned work typically is the result of assigning work that simply cannot be done: materials were not checked ahead of time for availability and cannot be found, work space still is occupied by other crews finishing prerequisite work (since they use a similar unreliable planning system, they can cannot accurately forecast when their work will be done), management pressured the foreman/superintendent into adding activities to the work plan to keep up the illusion that work was on schedule even though they did not believe it could be done, and so on. Consequently, work progresses at an unreliable pace, making it necessary for all on site to remain flexible and make last-minute opportunistic decisions as to what can be done at any one time. This defeats the purpose of planning altogether. More reliable planning makes it possible to improve production by reducing worker idle time and time spent looking for and fetching materials; it makes it possible to provide others on site with completion times that can be relied upon, in turn allowing them to improve the planning of their own work; and it allows for time to better plan!
Principles of The Last Planner
Schedules tell workers what they SHOULD do (Figure 1). Project management thereafter monitors and enforces conformance of DID to SHOULD. If this approach worked perfectly, DID would always match SHOULD. Actual measurement on successful projects reveals that what actually gets done in terms of planned activities ranges from 27% to 68% of planned activities completed, so there is a large discrepancy between the two. The lack of fit between SHOULD and CAN is substantial and systemic. Improving that fit can be achieved using The Last Planner.
Figure 1: Match between SHOULD and DID
The Last Planner principle is based on the premise that one should create reliable weekly work plans in order to derive the maximum benefits from the planning process. Such plans include only work for which it has been determined ahead of time that it can be done. The Last Planner is expected to make commitments (WILL) to doing what SHOULD be done, only to the extent that it CAN be done (Figure 2).
Figure 2: The Last Planner
To achieve this, The Last Planner must select assignments from a workable backlog comprising activities that meet three Quality Criteria: work must be (1) assigned in the right sequence, (2) assigned in the right amount to match labor and equipment capacity, and (3) be practical (design documents and materials must be on hand or in control, prerequisite work must clearly going to be done in time for the assignment to be carried out, and necessary coordination must have been identified and complete).
The Last Planner approach provides forward information for control because it forces problems to the surface at the planning stage. It makes it possible to gauge planning system performance (Figure 3).
Figure 3: Planning System Performance
Industry Application and Success
The Last Planner concept was developed and tested on actual construction projects by Glenn Ballard. Its application has improved productivity dramatically. A specialty contractor in building construction was able to increase operating profits from 5% to 30%. On major industrial projects it has been demonstrated that the productivity of crews that created more reliable plans (those able to complete more than 50% of the work they had planned, i.e., PPC > 50%) is 30% higher than that of crews with PPC < 50%.
The Last Planner is one of the principles of Lean Construction that Glenn Ballard has been advocating.To foster and develop this new production philosophy for construction, Glenn Ballard jointly with Lauri Koskela of VTT in Finland co-founded the International Group for Lean Construction in 1993 and annual conferences have been held since. In 1997, Glenn Ballard and Greg Howell started the Lean Construction Institute, an independent non-profit research organization to conduct research into and apply lean construction.
Note: All figures were taken from "Improving the Reliability of Planning: Understanding The Last Planner Technique" by Glenn Ballard and Greg Howell (1997).