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In a previous post, we discussed the opportunities and challenges of applying the lean principles of Set-Based Design in construction design.

Traditional construction design management has struggled with an ad hoc approach to design, increasing the amount of rework and cost, in addition to reducing the ability to produce efficient designs according to customer needs. These issues stem from the problem that current approaches to design management lack an orderly process of work which can be managed towards clear goals and thus value creation.

What is the Model Maturity Index framework?

Model Maturity Index (MMI) is a framework designed to describe the model progression in the BIM, using a series of levels increasing in maturity as the design process progresses towards a finalized design.

Built on the principles of Set-Based Design, the MMI framework provides a process of work, describing BIM development in a way which enables the possibility to manage it according to lean principles.The MMI-framework is built to be open source, and levels in intervals of 100 makes it possible for companies to add new levels where they see fit according to their practices. The MMI-framework as used in the cases in this study were as follows:

MMI 100: Concept/Sketch
MMI 200: Chosen concept
MMI 250: Chosen concept, detailed to the degree necessary for cost calculation.
MMI 300: Design, controlled for collisions and conflicts within the specific discipline.
MMI 350: Design, controlled for inter-disciplinary collisions and conflicts.
MMI 400: Finished design detailed to the degree necessary for production.
MMI 500: Finished design, designed as built.

Examples from Case Studies of Model Maturity Index

Our study of MMI assessed the plans and meeting documents of two pilot projects carried out by two of the three largest construction companies in the Norwegian AEC-industry. Both companies operated as turnkey-contractors managing both production and design of their respective projects.

The case-study found that the implementation of MMI was largely seen as a success. Participants of the two studies cited the following benefits:

  • Increased understanding of the current state of the BIM model
  • Increased understanding of needs and responsibilities
  • Increased sharing of incomplete information
  • Increased ability for project participants to express project development

In addition, the projects were found to deliver less faulty designs at a more predictable schedule, so much so that at least one of the companies has made its MMI-framework a mandatory part of their design practices going forward.

By charting the amount of collisions in the model within disciplines (left, relevant to MMI300) and between disciplines (right, relevant to MMI350), managers could track model progression towards completion of different milestones.

How to apply Model Maturity Index in construction design?

In the case study, five key aspects of implementation were identified as crucial for implementation in projects. In order to succeed with lean design using MMI, design managers needed to make sound decisions as to how they were to address each of the five aspects:

  1. Specification of maturity levels
    Management needs to describe the MMI-levels in a way that fits the work deliverables during design.
  2. Degree of Model Disaggregation
    Applications of the MMI-framework does not use MMI to indicate the maturity of every individual object in the model, seeing as this would make planning incomprehensible. Instead, MMI is used to indicate the maturity of larger sections in the BIM. In this regard, management needs to find the optimal amount of sections to segregate the model into.
  3. Communication of model maturity
    How are the constantly changing maturity of different parts of the model communicated to designers?
  4. Planning and control of workflow
    How are MMI incorporated into plans, and how are plans managed?
  5. Responsibility for assigning maturity
    Who is the responsible authority in declaring changes to the maturity of different parts of the model?

Concept chosen for communication of model maturity in the infrastructure projects, divided by sections on one axis and disciplines on the other.

Recommendations for implementation

A number of significant lessons can be taken from the cases:

  1. Specification of maturity levels
    Description of simple MMI-levels with binary options for task completion are needed for clarity in communication. Describing the requirement for achieving a level according to the function of delivery enables make-ready of future tasks.
  2. Degree of Model Disaggregation
    MMI was used to describe all objects relevant to specific disciplines (architectural, structural, etc.) within large sections of the model. Managing the maturity of larger disciplinary sections was found to ease planning, as it highlights the necessary interfaces between different designers to manage in the design process.
  3. Communication of model maturity
    Successful ways of communicating model maturity were highly visual, enabling designers to get an intuitive understanding of model maturity throughout design development.
  4. Planning and control of workflow
    In order to integrate model development into the design planning, all MMI-levels for every discipline were treated as specific deliveries using Last Planner and ICE-meetings.
  5. Responsibility for assigning maturity
    Due to an initial lack of specificity in definitions of MMI-levels, there was no universal understanding as to what constituted a MMI-delivery during the start of design development. As such, third party control of deliveries for stages such as 300, 350 and 400 proved to be necessary.

The management of larger sections of the model were found to be a key area of success for implementation.

In addition, some key success-criteria was observed:

  • In both cases, company leadership had carefully chosen to use the new implementation efforts with teams and people open to change and experimentation.
  • In both cases, design management had opted to a “learn to walk before you can run”-policy. Implementation efforts favored simplicity and practicality over complex approaches.

Lastly, it should be mentioned that when implementing new technologies, the focus of the implementation is to enable work, not to hinder it. Thus, the strategy as to how to approach maturity based design management should be to describe the work designers are already doing in a way which makes the work easier to plan and coordinate, instead of creating more needless work for the designers to do in addition to their existing responsibilities.

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Andreas is an award-winning scientist from the International Group of Lean Construction (IGLC) and a guest lecturer in lean design engineering at the Norwegian University of Science and Technology. Having experience as both a structural design engineer and a construction site manager, his greatest passion is translating complicated scientific findings into clear and actionable advice for those actually doing the work.