How to Use Plan Modules to Build Better Milestone Plans

Introduction

Milestone Planning is one of five core elements of the Last Planner System® (LPS®)[1] that building project teams use to plan and coordinate work. The LPS process represents a departure from traditional project critical path method (CPM) planning methods, recognizing that these methods hinder more than help the active management of work in a dynamic, complex environment.[2]

A long time ago, when I worked as a project controls consultant, a client asked me to create a project schedule that had absolutely no float, meaning that all work on this 3,000-activity CPM plan would be on a critical path. His intention was to game the owner change order process so that any change with a time impact resulted in a delay claim. This is one example of how low-bid construction contracts, CPM schedules, and adversarial relationships – the unholy trifecta of traditional project management – leads consistently to over budget and late projects.

Despite the drawbacks inherent in the CPM planning process many otherwise lean projects attempt to use a CPM approach to determine interim project milestones. Often several thousand tasks are detailed with estimated durations and arranged in staggered sequences that are plotted on a Gannt chart. Interim milestones are determined from these scheduled tasks. This detail is only ever accidentally accurate and hinders a strategic approach to planning a project.

Adding Strategy to Pull Planning

The ability to focus on establishing flow in work activities is an important advantage of LPS based planning. By incorporating a few key strategic planning elements into the pull-based process LPS prescribes for developing milestone plans, project leaders will introduce a higher level of control over project completion dates.

Strategic Planning Elements[3]

• Plan Modules
• Plan Increments
• Linearization and Level Crew Flow
• Operation Sets
• Release Pace

This article focuses on how to use the first of these elements, Plan Modules. Last Planner System practitioners currently organize their projects into phases. To optimize opportunities for strategically planning workflow and developing a sound milestone plan many project phases should be further organized into Plan Modules.

What is a Plan Module?

Plan Modules are the major workstreams for the project, beginning with design planning, running through construction completion, and finishing with the building opening. Some Plan Modules are arranged concurrently, and others arranged sequentially. The purpose of determining Plan Modules is to simplify the management and execution of a complex project requiring the coordinated skills of a large cross-section of different professional disciplines. This simplification is achieved by designating Plan Modules that to the greatest extent possible are decoupled from each other.

Decoupling is important because it limits the amount of coordination required between major parts of a project, thereby aiding the integration of those parts. Decoupling also serves to shield other parts of the project should a change in requirements or conditions impact one part of the project. Decoupling helps project leaders be able to respond to the inevitable unknowns that arise while reliably targeting a fast time to market for the project. This contrasts with the request by my client discussed in the introduction. He wanted a disruption anywhere to affect everything else.

How do You Determine How to Designate Plan Modules?

The process of designating Plan Modules begins with understanding who will be working on different elements of the project. Since at the beginning of a project most individuals who will be on the project team are unknown the professional skills required for the project serve as a useful proxy. While Plan Modules for the design, design production, and construction stage of a project serve the same purpose, there are different considerations for each of these stages.

Most construction Plan Modules require several separate independent steps performed by in many cases a few dozen or more people. Design production Plan Modules have fewer independent steps, with work passed from one smaller set of professionals to the next. Design Plan Modules organized in a work cluster fashion will have the same inter-disciplinary team working on a sequence of steps.

To designate Plan Modules, identify which groups of people can work together, largely independent of other groups, for a time to accomplish a major part of the project. Some of these Plan Modules will operate concurrently, while other with be dependent upon the partial or full completion of preceding Plan Modules.

What Are Examples of Plan Modules for Construction?

The Plan Module list that follows is based on a simplified version of a healthcare project. It is not prescriptive, even for the team working on this project, but rather a guide illustrating how to designate Plan Modules.

• Substructure
• Structure
• Envelope Type 1
• Envelope Type 2
• Roof
• Rough-In for Levels 0-2
• MEP Shaft and Service Rooms
• Overhead Main Rough-In for Levels 3-8
• Branch and In-Wall Rough-In for Levels 3-8
• Penthouse MEP Systems and Finishes
• Interior Finishes for Levels 0-2
• Interior Finishes and Above Ceiling Rough-In for Levels 3-8
• Site Hardscape and Landscape

What Are Examples of Plan Modules for Design?

The Plan Module list that follows is based, with some modifications, on the same healthcare project. Beyond concept design the list follows a typical LPS Target Value Delivery (TVD) work cluster style organization.

• Set-Based Concept Design
• Structural Engineering
• Envelope Design
• Conveyance Systems Planning
• HVAC/Plumbing/Fire Protection Engineering
• Electrical / Fire Alarm Engineering
• Building Interiors Design
• Technology and Medical Equipment Planning

The size and complexity of a project will affect how design Plan Modules are designated. The recommended guidance for design Plan Module organization is that no Plan Module should have more than ten members, and ideally have five to seven members. If you find more people are required for a Plan Module you will need to divide it into two or more modules.

Conversely, if you find that the same sets of people are in multiple work clusters then those clusters should be combined. I’ve witnessed this dynamic on smaller projects seeking to employ the TVD model. Keep in mind that work clusters are people that work together to progress the design, and not meeting groups to report on each other’s independent work. There is no such thing as independent work in a functioning design work cluster.

For large and/or complex projects a Set-Based Concept Design Plan Module may need to be divided into separate modules. These groups will need to use TVD integration events to coordinate design ideas as these Plan Modules are more tightly coupled than other Plan Modules.

Design production, the work of documenting the design in models, drawings, and submittal documents may have a smaller set of Plan Modules, each focused upon documentation for a set of design phase Plan Modules.

Where Do You Go from Here to Develop a Milestone Plan?

Other articles address the remaining Strategic Planning Elements and how they work together to inform a sound milestone plan. Those articles will be linked here and elsewhere as they are developed.

[1] Last Planner System® and LPS® are registered trademarks of the Lean Construction Institute.

[2] Construction scheduling can be accurately described as an “NP-Hard” problem, meaning that the due to the sheer number of variables that inform any complex schedule even a high-speed supercomputer is unable to calculate an accurate schedule in finite time. A relevant mathematical proof of the impossibility of accurate project scheduling is provided in the analogous Job-Shop Scheduling Problem description found at https://en.wikipedia.org/wiki/Job-shop_scheduling.

[3] The terms “Plan Modules,” “Plan Increments,” and “Linearization” used for these elements are adapted from the work of Gene Kim and Steven J. Spear in Wiring the Winning Organization, IT Revolution, 2023.