An input-process-output representation of design tasks or construction processes. The model depicts the specification of directives (entering the process rectangle from above), prerequisites (including materials and information to be transformed into the desired output, entering the process rectangle from the left), and resources (entering the process rectangle from below). It also shows an inspection process resulting either in redo or release to the customer process. The model is used as a guide to exploding scheduled tasks into a level of detail at which their readiness for execution can be assessed and advanced.
See activity definition model.
A directive or order given to a worker or workers directly producing or contributing to the production of design or construction.
See workable backlog.
A mechanism for deadening the force of a concussion; e.g., a capacity buffer is created by scheduling less than all the time available. If production falls behind schedule, there is capacity available for catching up. (Lean production/construction generally prefers capacity buffers to inventory buffers.)
The amount of work a production unit, whether individual or group, can accomplish in a given amount of time.
The bottom level in the planning system hierarchy, below lookahead planning, that results in commitments to deliver on which others in the production system can rely because they follow the rule that only sound assignments are to be accepted or made.
Directives, often criteria, imposed by the entity initiating a process (usually the owner) that specify how success of the outcome will be gauged.
Something that stands in the way of a task being executable or sound. Typical constraints on design tasks are inputs from others, clarity of criteria for what is to be produced or provided, approvals or releases, and labor or equipment resources. Typical constraints on construction tasks are the completion of design or prerequisite work; availability of materials, information, and directives. Screening tasks for readiness is assessing the status of their constraints. Removing constraints is making a task ready to be assigned.
To cause events to conform to plan, or to initiate replanning and learning .
See conditions of satisfaction.
Criteria are a subset of directives, specifically those used to evaluate process outputs.
The user of one’s output .
The time it takes a product to go from beginning to end of a production process; i.e., the time it is work-in-process .
Quality criterion for assignments that questions whether or not assignments are specific enough so that the right type and amount of information and materials can be collected, work can be coordinated with other disciplines or trades, and it is possible to tell at the end of the week if the assignment has been completed.
A type of goal-directed, reductive (not deductive) reasoning. There are always many possible designs, especially if one is willing to relax constraints. Product design reasons from function to form. Process design reasons from ends to means.
The characteristics required for acceptance of product or process design.
Instruction or order issued by a last planner™ to direct workers on what to do and possibly when or how to do it. Directives may apply to selection of prerequisites ,resources, process execution, or criteria for output evaluation. See ADM.
Expressing a task in greater detail, typically by producing a flow diagram of the process of which the output is the task being exploded, then determining the sub-tasks needed to make the task ready for assignment and execution when scheduled. Sub-tasks are categorized in terms of the activity definition model , resulting in actions to clarify or specify directives, requests for prerequisites from suppliers, and reservation of needed resources .
Trial execution of a process in order to determine the best means, methods, sequencing, etc. to perform it. First-run studies are done a few weeks ahead of the scheduled execution of the process, while there is time to acquire different or additional prerequisites and resources .
See work flow.
The top level in the planning system hierarchy, above lookahead planning, dedicated to articulating high-level activities and their duration and sequencing for an entire project and resulting in a master schedule. Also see lookahead planning and commitment planning.
The combination of directives, prerequisites, and resources needed to execute a process. See ADM.
Integrated Project Delivery is a delivery system that seek to align interests, objectives and practices, even in a single business, through a team-based approach. The team primary Team Members would include the Architect, key technical consultants as well as a general contractor and key subcontractors. It creates an organization able to apply the principles and practices of the Lean Project Delivery System. For more information see http://www.leanconstruction.org/lcj/V2_N1/LCJ_05_003.pdf
[IPD is a registered business mark by Lean Construction Institute with the US PTO]
Stock on hand; often divided between raw materials inventory, work-in-process, and finished goods inventory.
The person or group that makes assignments to direct workers. ‘Squad boss’ and ‘discipline lead’ are common names for last planners in design processes. ‘Superintendent’ (if a job is small) or ‘foreman’ are common names for last planners in construction processes.
The process of gaining new knowledge or insights whose implementation may improve product and process development.
The amount of output expected from a production unit or individual worker within a given time. Within a weekly work plan, what is to be accomplished by a design squad or individual designer, engineer, draftsperson, construction craftworker, crew, etc. A quality assignment ‘loads’ a resource within its capacity.
The middle level in the planning system hierarchy, below front end planning and above commitment planning, dedicated to controlling the flow of work through the production system.
The output of lookahead planning, resulting from exploding master schedule activities by means of the activity definition model, screening the resultant tasks before allowing entry into the lookahead window or advancement within the window, and execution of actions needed to make tasks ready for assignment when scheduled. Lookahead schedules may be presented in list form or bar charts.
How far ahead of scheduled start activities in the master schedule are subjected to explosion, screening, or make ready . Typically lookahead windows extend from 3 to 12 weeks into the future.
‘To make ready’ is to take actions needed to remove constraints from assignments to make them sound.
Schedule produced during front end planning and covering an entire project, with activities to be exploded when creating the lookahead schedule .
The product or service resulting from execution of an activity or process.
see PPC.
The extent to which a plan is an accurate forecast of future events, measured by PPC.
Defining criteria for success and producing strategies and directives for achieving success.
Percent plan complete; i.e., the number of planned completions divided into the number of actual completions, usually referring to activities on a weekly work plan.
Work done by others on materials or information that serves as an input or substrate for your work.
A group of direct production workers that do or share responsibility for similar work, drawing on the same skills and techniques.
The ratio of the output produced to the resources used in its production.
Initiating the delivery of input based on the readiness of the process into which they will enter for transformation into outputs.
A push system schedules the release of work based on demand, while a pull system authorizes the release of work based on system status (from Hopp and Spearman 1996 p. 317)
Releasing materials, information, or directives possibly according to a plan but irrespectively of whether or not the downstream process is ready to process them.
Assignment that meets quality criteria for release to the customer process.
(1) definition, (2) soundness, (3) sequence, (4) size, and (5) learning.
...for failing to complete weekly assignments; e.g., lack of prerequisites, insufficient time, unclear directives. Reasons can also be sought for failing to advance scheduled tasks from master schedule to lookahead schedule or from one week to the next within the lookahead schedule.
Labor or instrument of labor, including tools, equipment, and space. Resources have production capacities as well as costs. Consequently, materials and information are not resources, but rather what resources act on or process.
Determining the status of tasks in the lookahead window relative to their constraints, and choosing to advance or retard tasks based on their constraint status and the probability of removing constraints.
Quality criterion for selecting assignments among those that are sound in priority order and in constructability order.
Not releasing work to production units because it does not meet quality criteria; the work is not a quality assignment . It is akin to ‘stopping the assembly line.’ The purpose of shielding is the make production units less subject to uncertainty and variation, thereby providing them with greater opportunity to be reliable.
To be effective, production management systems must tell us what we should do and what we can do, so that we can decide what we will do, then compare with what we did to improve our planning.
Quality criterion whereby the amount of work included in an assignment is made to match the capacity of the production unit that will do the work.
Quality criterion for assignments that questions whether or not assignments have had all constraints removed.
The provider of needed inputs: prerequisites (including materials and information), resources, directives, etc.
The time from sending a request for delivery to the delivery.
Type and amount of work assigned to a production unit .
The output rate of a production process.
Making assignments to a production unit or resource within a production unit that absorbs less than 100% of its capacity. Underloading is necessary to accommodate variation in processing time or production rate, in order to assure plan reliability. Underloading is also done to release time for workers to take part in training or learning, conducting first-run studies, implementing process improvements, or for equipment to be maintained.
The percentage of a resource’s capacity that is used in production.
A list of assignments to be completed within the specified week; typically produced as near as possible to the beginning of the week.
How far in advance future work completions are accurately forecast.
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.
The movement of information and materials through a network of production units, each of which processes them before releasing to those downstream.
Causing information or materials to move through a network of production units in a desired sequence and at a desired rate.
The inventory between the start and end points of a production process.
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.
