Glossary Decisions & governance
What is a technology readiness level?
A technology readiness level (TRL) rates a technology's maturity on a scale from 1, basic principles observed, to 9, proven in actual operation.
Also called TRL.
Technology readiness level (TRL)
Technology readiness levels are a scale for rating how mature a technology is, from TRL 1, basic principles observed, to TRL 9, the actual system proven in operation. The scale was developed at NASA, is used by the US Department of Defense, the European Space Agency and others, and is defined for space systems in ISO 16290. A level is reached by evidence, such as a demonstration in a relevant environment, not by effort spent.
Why it matters
A design is only as ready as its least mature technology. Rating maturity early shows where the risk is, where a fallback is needed, and which parts need development before the system can be built.
How it goes wrong
- Rating a component without asking whether it has been shown in this system's environment
- Reporting a system's readiness from its most mature parts instead of its least mature
- Treating a readiness level as a schedule promise rather than a record of evidence
In Cairn
Cairn does not use TRL numbers. The Causality lens gives each part a maturity stage: concept, prototype, in development, tested, in production or mature, or deprecated for something being phased out, with a confidence and notes. These stages are Cairn's own and are not TRLs. The lens sets a node's parts on Harney's Pyramid of Causality and shows that the system can be no further along than the least mature part it rests on, naming that limit. Stages are set by hand in the inspector or assessed by AI through Change Review, and an AI assessment never overwrites a stage a person set.
Questions
- Who uses TRLs?
- NASA, where the scale was developed, the US Department of Defense, the European Space Agency, and many research funders and companies, often with their own wording for each level.
- Does Cairn assign TRLs?
- No. It records maturity stages such as prototype or tested, which are not TRLs, and it does not convert between the two.
See it on your own system.
Describe what you are building and Cairn interviews you, then builds the first model with you.