Last Planner System

Core components

• Four interconnected planning levels: master scheduling (project-level milestones), phase scheduling (reverse-pass collaborative planning by all parties involved in the phase), lookahead planning (6-week rolling window with constraint analysis and make-ready), weekly work planning (commitments by Last Planners)
• Reverse-pass phase scheduling (pull planning): collaborative session in which trades plan a phase starting from completion milestone and working backward through pull-based commitment
• Make-ready process: identifying and removing constraints (prerequisite work, materials, information, resources, permits, weather) before activities are scheduled into weekly plans
• Should-Can-Will distinction: SHOULD reflects master-plan intent
• CAN reflects what is actually feasible after constraint analysis
• WILL reflects committed work for the week
• Last Planner commitment: typically foreman or superintendent making specific weekly commitments
• Percent Plan Complete (PPC): proportion of committed tasks actually completed in the week (typical good performance 75-90%)
• Reasons for Variance analysis: investigation and recording of why missed commitments occurred, with structured categories (prerequisite work, materials, information, labor, equipment, weather, etc.)
• Continuous improvement loop: variance analysis informs future planning
• Integration with Building Information Modeling (BIM), Integrated Project Delivery (IPD), and Target Value Design (TVD) in lean-construction tool ecosystem

Primary use case

Production-control system for construction projects, particularly complex multi-trade commercial and infrastructure projects; applied principally in: healthcare construction, commercial high-rise, manufacturing facility construction, infrastructure projects (transportation, utilities), large public-sector projects; complementary to broader lean construction practices: Target Value Design, A3 problem solving, big-room collaboration, set-based design; compatibility with CPM master schedules: LPS provides the production-control layer below the strategic CPM level rather than replacing CPM; academic and professional reference in lean construction, construction management, and project-management research; international diffusion through Lean Construction Institute affiliates in Australia, Brazil, Chile, UK, Norway, and others; research empirical base: substantial peer-reviewed literature documenting PPC improvement and project-performance gains in LPS implementations.

Common criticisms

• LPS empirical evidence has been substantially debated — while substantial peer-reviewed literature documents positive outcomes (PPC improvements, schedule reliability gains, productivity improvements in case studies), the evidence is dominated by case studies and surveys rather than controlled experiments, with selection bias toward successful implementations
• the 'reasons for variance' categorization is methodologically simple but practitioners report substantial difficulty in honest variance reporting when client and contractor relationships are adversarial
• implementation faces substantial cultural barriers in construction's traditionally adversarial contractor-subcontractor and contractor-client relationships, with LPS's collaborative pull-planning sessions requiring substantial trust that does not always exist
• the method's success in particular projects depends substantially on contractor and trade buy-in, leadership commitment, and project-context factors that are not always present, producing implementation variability
• interaction with traditional CPM master schedules and contractually-required schedule documentation produces implementation complexity — LPS adds layer rather than replacing existing CPM
• pure-LPS implementation versus partial-LPS adoption produces practice variation that complicates empirical evaluation
• commercial-coaching and certification infrastructure (Lean Construction Institute certification, consulting practices) raises ordinary concerns about institutional incentives shaping framework promotion
• cross-cultural applicability is uneven — LPS has substantial adoption in Anglophone construction and in Latin American construction industries but has been argued to require substantial adaptation in other cultural contexts
• integration with technology (BIM, scheduling software, IoT-enabled construction monitoring) is developing but incomplete.