Unlike classic approaches where one solution is often selected very early and then continuously corrected, Set-Based Design seeks to:
- keep several options open,
- learn progressively,
- and make more robust decisions at the right time.
The objective is not to delay decisions unnecessarily.
The objective is to avoid:
- premature trade-offs,
- costly rework,
- and choices that degrade the project's overall value.
Simple definition
In a classic design approach:
- one solution is chosen quickly,
- then optimized as the project progresses.
The problem is that:
- some constraints appear late,
- real impacts are poorly known,
- and modifications become expensive.
Set-Based Design works differently.
Instead of immediately converging toward a single solution, teams:
- explore several options,
- compare their impacts,
- progressively eliminate the least relevant ones,
- then converge toward a more robust solution.
Lean considers that:
the more critical decisions are made with a complete understanding of constraints and impacts, the more stable the project becomes.
Why it matters
In many projects:
- some decisions are frozen too early,
- before real constraints are sufficiently known.
The result:
- design rework,
- late trade-offs,
- cost overruns,
- loss of value,
- and project instability.
Teams then spend their time:
- correcting,
- adapting,
- or working around decisions that have become problematic.
Set-Based Design instead seeks to:
- maintain learning capacity for longer,
- improve the quality of trade-offs,
- and reduce irreversible decisions made too early.
This approach is particularly useful when:
- projects are complex,
- interfaces are numerous,
- technical stakes are high,
- or operational impacts are significant.
Concrete example
On a hospital project:
several facade solutions are considered.
In a classic approach:
one option is chosen very early,
then problems gradually appear:
- cost,
- maintenance,
- logistics,
- energy performance,
- constructability.
Modifications then become:
- long,
- expensive,
- and conflict-prone.
With Set-Based Design:
- several solutions are studied in parallel,
- impacts are compared progressively,
- and some options are eliminated as learning accumulates.
The project then converges:
toward a more robust solution,
better aligned with:
- objectives,
- constraints,
- and the project's overall value.
Common mistakes
Freezing decisions too early
A premature decision can generate:
- rework,
- late trade-offs,
- and a significant loss of value.
Confusing exploration with absence of decision
Set-Based Design remains a structured and steered approach.
Studying too many options without progressive convergence
The objective is not to maintain infinite complexity.
Working in silos
Trade-offs become more effective when:
- interfaces,
- uses,
- and operations
are integrated early.
Considering rework inevitable
Set-Based Design specifically seeks to reduce unnecessary iterations.
Indicators to track
Set-Based Design can be steered with several indicators:
- Number of design iterations
- Number of rework loops
- Decision lead time
- Cost of late modifications
- Level of constructability
- Target cost adherence
- Stakeholder satisfaction
- Number of options compared
- Life-cycle performance
- Study variability
- Quality of trade-offs
- Number of interface conflicts
The objective is to measure:
- decision robustness,
- and the progressive stability of the design system.
Frequently asked questions
Why not immediately choose the "best" solution?
Because some critical information appears progressively over the course of the project.
Does Set-Based Design slow design down?
Not necessarily. It often reduces:
- rework,
- late trade-offs,
- and costly corrections.
What is the difference with a classic option study?
Set-Based Design integrates:
- collaboration,
- progressive learning,
- and structured convergence.
Do all projects need Set-Based Design?
The approach is particularly relevant:
- when interfaces are complex,
- technical stakes are high,
- or operational impacts are significant.
What is the link with Lean?
Set-Based Design applies Lean principles of:
- learning,
- waste reduction,
- and improving value creation.
Leanfinity offer link
Target Value Delivery / Lean Engineering
Leanfinity supports organizations in:
- implementing Lean design approaches,
- improving trade-offs,
- coordinating interfaces,
- and seeking robust solutions oriented toward overall value.
Our objective:
help projects make:
- better decisions,
- at the right time,
- with a better understanding of real impacts.
How it works
Define
Clarify the concept and its role in the operating system.
See
Make flows, constraints, gaps, and interfaces visible.
Act
Turn the principle into concrete routines, decisions, and commitments.
Learn
Measure gaps to improve the system without looking for someone to blame.
Set-Based Design is based on several Lean principles.
Explore several solutions
Teams develop several options:
The objective is to better understand:
Work collaboratively
Different stakeholders participate in trade-offs:
Constraints become visible earlier.
Progressively eliminate options
Over time:
some solutions are set aside,
based on:
Delay irreversible decisions
Lean seeks to freeze choices:
Learn before converging
The project progressively builds: