Knowledge Center > Glossary > W



The state of a resource (e.g., worker or production unit) when it is not in use (could be use in production or maintenance). One of 7 wastes.


Anything with a cost of any kind, the elimination of which does not reduce value delivered.

→ see 7 Wastes, muda, muri, mura

Weekly Work Plan, Commitment Plan [LPS]

A list of quality assignments to be completed within the specified time period that have been reviewed and committed to by the last planner; typically committed as near as possible to the beginning of that time period (here: a week).

Master-, phase-, and lookahead (or make-ready) plans of course also must have activities that people commit to performing!

The list should be produced 2-3 weeks (or other lead time deemed necessary) before commitment in order to identify and remove constraints and to measure success in making ready.

Whole Life Target Value Design [TVD]

Target Value Design pursued while taking into account not only Design, Construction, and Operations and Maintenance, but also Business Costs and Outcomes.

→ see Target Value Design

window of plan reliability

How far in advance future work completions are predictably forecast.

Example: If you can predictably forecast only 1 day in advance when work will be completed, then your window of reliability is 1 day.


→ see work-in-process

work balancing, work load balancing

Reassigning work that was assigned to one individual or production unit to be done by another individual or production unit in order to even out the amount of time each needs to complete their work.

Related → see load leveling

work flow

The movement of information and materials through a network of production units, each of which processes them before releasing to those downstream.

work flow control

Causing information or materials and assignments to move through a network of production units in a desired sequence and at a desired rate.

work structuring

Process of breaking work into pieces, where pieces will likely be different from one production unit to the next, so as to promote flow and throughput. Work structuring answers the following questions (Ballard 1999, Tsao et al. 2004):

  • In what units will work be assigned to groups of workers?
  • How will work be sequenced?
  • How will work be released from one group of workers to the next?
  • Will consecutive groups of workers execute work in a continuous flow process or will their work be decoupled?
  • Where will decoupling buffers be needed and how should they be sized?
  • When will different units of work be done?

Work structuring is a dynamic process to be re-evaluated in the course of a project. At the project onset, work structuring deals with designing the overall system. As the project progresses, work structuring becomes more focused to guide the design and execution of interacting pieces of impending work.

Ballard, G. (1999). “Work Structuring.” LCI White Paper-5, June.
Howell, G., Laufer, A., and Ballard, G. (1993). “Interaction between Subcycles: One Key to Improved Methods.” ASCE, J. Constr. Engin. Manage., 119 (4) 714-728.
Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and Howell, G.A. (2004). “Work Structuring to Achieve Integrated Product-Process Design.” ASCE, J. Constr. Engin. Manage., Nov/Dec, 130 (6) 780-789.

workable backlog [LPS]

In the Last Planner System, assignments that have met all quality criteria, except that some must yet satisfy the sequence criterion by prior execution of prerequisite work already scheduled. Other backlog assignments may be performed within a range of time without interfering with other tasks. Workable backlog can be used when capacity becomes available during execution of a work plan (e.g., when some work on a weekly work plan cannot be executed for some reason).

Example: Those spare parts lists don’t have to be completed for 3 months, but it won’t harm anything if they are produced earlier, so use them as fallback or fill-in work when needed.

work-in-process (WIP)

The units or quantities of materials between the start and end points of a production process.

Illustration → see inventory