Knowledge Center > Glossary > M


(to) make ready

To take actions needed to remove constraints from tasks (assignments) in order to make them sound.

make-ready plan [LPS]

The output of make-ready planning, resulting from exploding master- or phase-schedule activities by means of the activity definition model, screening the resultant tasks before allowing entry into the make-ready window or advancement within the window, and taking actions needed to make tasks ready for assignment when scheduled. It is dedicated to controlling the flow of work through the production system. Make-ready plans may be presented in list form or bar charts.

NOTE: a make-ready plan is a kind of lookahead schedule, specifically one developed using the principled approach of the Last Planner System. We avoid using lookahead as it is a term used in practice also on non-lean projects.

make-ready planning [LPS]

The process of taking activities from the master- or phase schedule to the make-ready plan (lookahead plan), and then exploding, screening, or making them ready in a lookahead window.

make-ready (time) window [LPS]

How far ahead of scheduled start activities in the master- or phase schedule are subjected to explosion, screening, or making ready. Typically make-ready (time) windows extend from 3 to 12 weeks into the future. It is assumed that the duration of this window is defined in function of the ability to pull material to site. This duration depends on your ability to predict in advance at the task level what work needs to be done in the future. The greater the uncertainty in the system, the later tasks can be broken down into operations.

Management by Means (MBM)

A mindset and approach for managing an organization or company that relies on nurturing people, organizing work systematically, and continuously improving on standard processes.
Characterization of the living systems approach adopted in the Toyota Production System and in Scania’s modular design of trucks.

→ in contrast with management by results

Reference: Johnson, H.T. and Bröms, A. (2001). Profit Beyond Measure: Extraordinary Results through Attention to Work and People. Simon and Schuster, 272 pages.

Management by Results (MBR)

A mindset and approach for managing an organization or company that relies on hitting financial targets and other output metrics.

The contrast between driving work with financial targets (MBR), and organizing work systemically (MBM) was clearly enunciated by Edward Deming several years ago: “If you have a stable system, then there is no use to specify a goal. You will get whatever the system will deliver. A goal beyond the capability of the system will not be reached. If you do not have a stable system, then there is no point in setting a goal. There is no way to know what the system will produce.”

→ in contrast with management by means

Reference: Johnson, H.T. and Bröms, A. (2001). Profit Beyond Measure: Extraordinary Results through Attention to Work and People. Simon and Schuster, 272 pages.

Market Cost (MC) [TVD]

In Target Value Design, what an owner may expect to pay for a desired asset based on comparison to historical market cost for similar assets. Hence, it is the initial expected cost determined through benchmarking to market of the owner’s wants. The comparison to allowable cost determines whether or not to proceed with validation. It comes into play in business planning or in the course of the budget validation.

mass customization

The process of making a generic product customer specific. This may be done by fabricating components and stocking them, so they will be readily available when the customer specifications become known.

→ see Assembled To Order

master plan, master schedule

Plan or schedule covering an entire project start-to-finish, then further detailed and validated in phase planning, the activities in which are then exploded when creating the make-ready plan.

master planning, master scheduling

Development of a master plan (schedule), typically with the involvement of only high-level project participants (e.g., the general contractor) and done well in advance of the start of a project. In traditional practice, the exploration required to decide if to accept the challenge of meeting a target completion date is confused with determining a master schedule, which-in the lean philosophy-should be kept at milestones, to be progressively detailed phase by phase, collaboratively using phase planning (or pull planning) with those who are to do the work in each phase.

matching problem

Challenge encountered when combining unique products with other unique products, e.g., combining {a, b, c, …} and {1, 2, 3, …} in that order to form {a1, b2, c3, …}.


Image source: Iris D. Tommelein


→ see Management by Means


→ see Management by Results

merge bias

Phenomenon that occurs when two or more parallel paths of activities must be completed in order for the successor activity to start. Given that each path has its probability of governing the start time of that successor, all path probabilities must be combined in order to describe the likelihood of the successor starting.

Ignoring merge bias results in schedules being too optimistic (short) in their duration.

G_merge bias

Image source: Iris D. Tommelein


A point in time on the master plan (master schedule) that defines the end or beginning of a phase or a contractually required event.

mistakeproofing, poka yoke

The practice of designing products or processes to eliminate (or at least to reduce) the likelihood or impact of mistakes in use or execution.

Mistakeproofing and the Work Operations Framework
Mistakeproofing and the Work Operations Framework

Figure by Iris D. Tommelein, after Figure 6 in Tommelein and Demirkesen (2018)

Shingo, Shigeo (1986). Zero Quality Control: Source Inspection and the Poka-Yoke System. Taylor & Francis.

Tommelein, I.D. and Demirkesen, S. (2018). Mistakeproofing the Design of Construction Processes Using Inventive Problem Solving. CPWR, Silver Spring, MD, 60 pp., online at or


The Japanese word for a three-part problem prevention process developed at Toyota called GD3 or “Good Design, Good Discussion and Good Dissection.”

McLeish, James and Haughey, William (no date). “Introduction to Japanese Style Mizenboushi Methods for Preventing Problems Before They Occur.” visited 9 March 2015.
Yoshimura, Tatsuhiko (2002) Toyota Style Mizenboushi Method – GD3 Preventive Measures – How to Prevent a Problem Before it Occurs. In Japanese, Tokyo, JUSE Press.


The design practice that involved identifying groupings of parts to be configured in different ways thanks to clearly defined interfaces.

Reference: Baldwin, C.Y. and Clark, K.B. (2000). Design Rules, Volume 1: The Power of Modularity. MIT Press, 483 pp.


One of 7 wastes defined by Ohno (1988) referring to unnecessary movement by people.


→ see Made To Order


→ see Made To Stock


The Japanese word for waste referring to anything that fails to add value to the product or service delivered to the customer, i.e., anything unnecessary.

Muda is broken down into Ohno’s (1988) 7 Wastes.

Related → see muri and mura

multi-functional diagram, swimlane diagram

→ see cross-functional diagram

(to) multiskill

Process whereby production units—individuals or groups specialized in one skill or technique—acquire skills and techniques typically used by other production units.

→ also see (to) specialize


The Japanese word for waste stemming from unevenness or inconsistency of workload imposed on people or machines (resources). It may be alleviated through application of heijunka and kanban systems.

Related → see muri and muda


The Japanese word for waste stemming from overburdening people or machines (resources). It may be alleviated, for example, through application of 5S.

Related → see mura and muda