The following examples are typical constraints we may find: In the text and images below, I’ve categorized the typical variances in the Last Planner System into both definitions.Ĭonstraints most often appear during the planning process in pre-construction as part of system design. The signal that we should receive when we hear about a roadblock is to “REMOVE IT IMMEDIATELY!” Meaning, the items shown on constraint boards are things that, if not removed, will slow or stop the train of trades from moving effectively through zones. Most references to constraints in construction are actually roadblocks. Why does it matter? Reason 1: Words matter, and we want to signal the right action for the right word. Whether you imagine that sequence of trades as a train (like in Takt Construction) or a caravan of cars on a road, the point is the same-the roadblock will hold up the flow of work or the train of trades, and it is ALWAYS removed to create flow. A roadblock is anything that can hold up the progress of work done in a sequence or train of trades in construction. One definition for a roadblock is “a barrier of barricade on a road” or “any hindrance.” Words associated here are barrier, barricade, blockade, obstruction, or checkpoint. These are planned, leveled, optimized, and improved as a part of the Takt Steering & Control System and cannot be entirely removed-just improved.
Constraints for trades and crews are production rates, crew composition, crew labor availability, or zone configuration. In fact, the system is designed around it or with it in mind. They are accepted, adjusted, and improved as a part of the production system. They are dealt with differently than a roadblock. They are things that, once improved as best we can, we just must deal with and plan around.
In manufacturing, the constraint is often referred to as a bottleneck.”Ĭonstraints in project conditions and zones are permanent or semi-permanent. The Goal by Eliyahu Goldratt of Theory of Constraints’ fame defines constraint as: “the limiting factor (i.e., constraint) that stands in the way of achieving a goal and then systematically improving that constraint until it is no longer the limiting factor. One definition for a constraint is a “limitation or restriction.” Words like restriction, limitation, check, restraint, control, damper, rein, and hindrance are associated with the word. We will have better results, and it will frame our vocabulary to prepare for the current and inevitable pairing of Last Planner with Takt & Scrum.
I’m not picking a fight and don’t criticize anyone who has used the term constraints to encompass both “constraints” and “roadblocks.” The term has served us well.īut the time has come to define and separate out the term “roadblocks” for the Last Planner System. Now, it’s time to split the term and call the roadblocks “ roadblocks” and to call the actual constraints “ constraints!” By introducing the proper use of these terms for our Last Planner meetings, we will all reap success. Calling possible and actual variants “constraints” was a great start for better construction management.
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