Technology Readiness Level (TRL)

Technology readiness level is a one-to-nine scale describing how far a technology has moved from idea to operation. One is an observed basic principle. Four is validation in a laboratory. Six is demonstration in a relevant environment. Nine is a system proven in operational use.

Calls state the levels they expect at start and at end, and the statement is binding in spirit even where it is not a formal eligibility condition. Research and innovation actions typically span levels 2 to 5; innovation actions span 5 to 8; the EIC Accelerator expects a starting point around 5 or 6 and an exit near 8 or 9.

The number is self-assessed, and evaluators judge the claim rather than accepting it. Two failure modes are common and both are expensive. Claiming a level higher than the evidence supports invites the reviewer to ask for the validation data that does not exist. Claiming a level below the call's range makes the proposal ineligible in substance. It is simply the wrong instrument.

The gap between levels 4 and 6 is where most European projects live and where most of them stall. Moving from a laboratory validation to a demonstration in a relevant environment means real conditions, real interfaces, real users and real failure rates. Proposals routinely underestimate that step, and reviewers routinely notice.

Be concrete about the environment rather than the number. A reviewer trusts a proposal that says what was tested, under what conditions, against what benchmark, and what remains unproven, far more than one that asserts TRL 6 and moves on.