Lauri Koskela’s CIFE Technical Report #72 argued that construction should be managed as a production system, not just as separate tasks and contracts. This reframing helped set the intellectual foundation for “lean construction,” including later work on planning reliability and workflow.
In a 1993 conference paper, Koskela reviewed “lean production” ideas and analyzed how they could apply to construction. This helped move lean construction from a concept into an applied research agenda focused on flow (smooth handoffs) and waste reduction.
The International Group for Lean Construction (IGLC) began holding annual conferences in the early 1990s, creating a shared forum for academics and practitioners. This community supported the spread of core ideas—especially improving workflow reliability and learning from field experiments.
By 1994, Glenn Ballard and Gregory Howell reported early lean construction implementation work aimed at stabilizing workflow on projects. These experiments emphasized making workable commitments and reducing variability, which became core to what was later formalized as the Last Planner System (LPS).
Ballard and Howell’s journal article argued that production control depends on the quality of work assignments given to crews (for example, whether tasks are “sound,” properly sequenced, and sized). This research strengthened the case for short-cycle planning and constraint removal—key mechanisms later used in LPS.
After the Lean Construction Institute (LCI) formed in 1997, it created a practitioner-focused network for training and knowledge sharing. LCI’s first Congress in Portland, Oregon, helped the emerging community share methods such as pull planning and early versions of the Last Planner System.
Glenn Ballard’s 2000 thesis defined the Last Planner System as a production-control approach that complements traditional project control (which often focuses on detecting problems after the fact). It emphasized improving “plan reliability,” commonly tracked with Percent Plan Complete (PPC), and learning from reasons plans fail.
By the mid-2000s, major owners began pairing lean planning with “relational” contracts that align incentives across key parties. Reports on Sutter Health describe early projects using an Integrated Form of Agreement (IFOA) to support collaboration and shared accountability instead of blame-driven change orders.
As lean construction matured, legal and commercial structures evolved to support integrated work. Will Lichtig’s work (often summarized as the “Five Big Ideas”) helped translate lean collaboration into contract language that encourages shared goals, early involvement, and joint risk/reward.
By 2007, Sutter Health was using multi-party agreements and “big room” collaboration to coordinate designers, builders, and key trades early. Trade press described these projects as demonstrations of integrated project delivery (IPD) paired with lean methods to reduce rework and stabilize workflow.
ConsensusDocs’ 300 multi-party IPD agreement provided an industry-standard “integrated form of agreement” structure for owners, designers, and constructors. The document explicitly connects IPD contracting with lean practices (such as pull planning and target value design), supporting broader adoption beyond one-off custom contracts.
By the early 2010s, lean construction and the Last Planner System had moved from small experiments into a more standardized set of practices taught through industry organizations. LCI continued convening large annual events, while the IGLC conference series provided the main research pipeline refining LPS, production system design, and integrated delivery methods.
Lean Construction movement and the Last Planner System (1990–2015)