Knowledge Center > Glossary > B



In planning →  see workable backlog

backward pass calculation [CPM]

Calculation of the late finish date and late start date of an activity in a network, taking into account the activity precedence relationships, by starting from the end of the schedule.

(to) balance

Matching load to capacity. Matching demand with supply.


The number of units that are being worked on simultaneously before a process produces output (production batch) or the number of units that together are being handed off from one production unit to the next (transfer batch).

A goal of lean is to achieve single-piece flow, that is, use batches of size 1 (1 being the unit the customer wants).

(to) batch

The practice of creating a batch or batches.

batch flow

Production system whereby processing stations (machines) are laid out by functional grouping so that each unit being produced is likely to have to follow a jumbled flow from one to the next, according to the processing steps it requires.

G_batch flow

Figure source: Schmenner (1993)

Reference: Schmenner, R. W. (1993). Production/operations management: from the inside out. Macmillan College.

Big Room, Oba, Obeeya

A designated place for a team to co-locate, engage in collaborative problem solving, and maintain a visual workplace.


→ see Building Information Model(-ing)


→  see Built-in Quality


The production unit with the lowest throughput (longest cycle time) of all production units in a system (the choke point) that is linear, sequential, and deterministic.

In other systems, bottlenecks also exist but they may be harder to pinpoint. Moreover, due to the possible inter-relatedness of parts and dynamic, stochastic characteristics of a system, its bottleneck(s) may shift over time.


Deviation from standard process or target outcome(s).

Types of breakdowns:

  1. Near misses, accidents, injuries
  2. Errors, defects, rework
  3. Broken promises, plan failures

Breakdowns provide learning opportunities because either

  1. we did not properly perform process A and need to learn how to do so, or
  2. our knowledge regarding causality “IF A THEN B” is inadequate.

broken promise → also see reliable promise

plan failure → also see quality criteria [LPS]


A mechanism for deadening the force of a concussion; e.g., a capacity buffer is created by scheduling less than all the time available (aka. underloading the production unit or other resource). If production falls behind schedule, there is capacity available for catching up. Capacity buffers may be preferred over inventory buffers. In addition to capacity and inventory buffers, other types of buffers are time buffers, monetary buffers (contingency), and spatial buffers (tolerances or allowable dimensional variation). Arguably, monetary buffers can be converted into, e.g., capacity buffers or inventory buffers.

A decoupling buffer is a kind of inventory buffer in-between two processes, large enough and replenished so that the second process can proceed at its own pace without being held up by the first.

buffer management

The selection, location, and sizing of buffer types within a production system in order to absorb variations in that system. It can include the modification of one or several of those selections as the project moves through time.

For example, buffers may be constrained (limited to a maximum size) by implementing pull using kanban or CONWIP.

Building Information Model(-ing) (BIM)

The process of generating and managing building data during the life cycle of a building.

The system comprising an integrated database, one output of which is a 3-dimensional model. 3D BIM refers to the 3-dimensional geometrical model, including spatial relationships, geographic information, and non-spatial properties of building components and systems. 4D also includes time so it may allow for simulation of the building assembly process. 5D further includes cost data so it may allow for cost modeling. 6D refers to a BIM annotated with data so it may support facility life-cycle management.

Built-in Quality (BiQ)

Quality achieved by work structuring, including designing operations so as to meet customer requirements, removing constraints, preparing workers, mistakeproofing and performing successive inspection during each processing step, as well as at each handoff; i.e., designing and executing the processes of making things so those products conform to requirements.
BiQ aims to avoid the reliance on end-of-line inspection and correction to achieve conformance to requirements.

G_BiQ process 2016-01-19

Figure source: (c) 2015, Iris D. Tommelein