Symbiosis in Development (SiD) is the framework Except uses for every project. Developed over 25 years across more than 700 engagements on six continents, it integrates systems thinking, network theory, and lifecycle analysis into a single operational method for designing at systemic scale.
SiD is open-source and freely available under Creative Commons BY-SA 4.0 licensing. The complete 480-page omnibus book, training materials, and quick guides can be found at thinksid.org.
Sustainability problems are systemic. A building is not just a building: it is a node in energy networks, water systems, transport grids, economic circuits, governance structures, and social contracts. Intervening at one point without understanding these connections produces rebound effects, cost overruns, and missed opportunities.
Most approaches treat sustainability as a checklist of isolated metrics. SiD treats it as a property of whole systems. The difference determines whether a project achieves incremental improvement or structural transformation.
A precise definition matters because it determines what you measure, what you optimise for, and what you miss.
Sustainability is a state of a complex and dynamic system. In this state, a system can continue to flourish without leading to its internal collapse or requiring inputs from outside its defined system boundaries. When applied to our civilisation, this state is consistent with an equitable and healthy society, thriving ecosystems, and a beautiful planet.
The critical word is state. Sustainability is not a physical constant or a fixed target. It is a dynamic condition that emerges from the relationships between a system's components. This means the primary unit of analysis is the relationship, not the object.
SiD structures every analysis through three nested levels, known as the SNO hierarchy:
Most sustainability work starts and ends at the object level: make the building more efficient, reduce the product's carbon footprint. SiD starts at the system level and works downward. A highly efficient component in a poorly configured network still produces a failing system.
At the object and network level, SiD uses the ELSI framework to ensure completeness. ELSI replaces the triple bottom line (people, planet, profit) with four causally nested dimensions:
These four expand into eight sub-categories (ELSI-8) for detailed analysis. The nesting is causal: individual wellbeing depends on functional societies, which depend on living ecosystems, which depend on stable energy and material flows.
The method translates theory into structured action through iterative cycles of analysis and synthesis:
These cycles are embedded in a broader four-phase process: Initiation (team building, process planning), Intelligence (research, data analysis, quick-scan), Innovation (co-creation sessions running the method cycles), and Development (feasibility, refinement, action planning).
SiD evaluates sustainability at the system level through three composite indicators:
These three indicators are fed by the network and object indicators identified through ELSI analysis. Together they provide a compact but comprehensive measure of whether a system is moving toward or away from sustainability.
At Except, SiD is not a theoretical overlay. It is the operating method for every project. When we design a masterplan, the ELSI analysis runs in the first week. When we develop a building concept, the SNO hierarchy structures the brief. When we create a product strategy, the backcasting method defines the roadmap.
The framework scales across all four disciplines. Urban planning projects use it to coordinate energy, water, mobility, and governance across entire districts. Architecture projects use it to stress-test designs against ecological, social, and economic risk. Landscape projects use it to set biodiversity targets and drainage capacity before form is decided. Product and service design projects use it to embed lifecycle thinking from the first specification.
The complete framework is documented at thinksid.org. The omnibus book is available as a free digital download. Quick guides are available in English, Japanese, and Traditional Chinese. Video training courses cover fundamentals and advanced applications.
Except runs SiD masterclasses for organisations and teams: intensive workshops covering the full framework with real project material.