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Technology readiness level is a nine-point scale that NASA built to stop programme managers from confusing a promising result with a working system. Applied to biology it is imperfect — a drug's TRL says nothing about whether the biology is right — but it does something no adjective can: it separates what has been demonstrated in a person from what has been demonstrated in a mouse, a dish, or a paper.
Nothing in the corpus sits at this level under the current filters.
Readiness levels describe technologies and interventions. Concepts, people, organizations, events, and risks do not have one — an argument is not a prototype. They are graded on evidence instead.
Routine clinical, commercial, or scientific practice today.
Approved or deployed, but early and narrow in scope.
Works in animals or small human studies. Not approved.
No working demonstration. Rests on argument or extrapolation.
Claims are actively disputed, or the practice is widely condemned.
A completed event, a superseded idea, or finished work.
How far something has been built says nothing about how hard it is to undo. Reading down a column shows what a given stage of development contains; reading across a row shows how much of the field commits a person to a permanent change. The bottom-left is the cell that deserves the most scrutiny: interventions that are hard or impossible to reverse and have not yet been shown to work.
| Reversibility | ConceptTRL 1–2 | LaboratoryTRL 3–4 | TranslationTRL 5–7 | DeployedTRL 8–9 | All |
|---|---|---|---|---|---|
| Reversible | — | 7 | 8 | 10 | 25 |
| Partly reversible | — | — | 1 | 1 | 2 |
| Context dependent | — | 4 | 5 | 4 | 13 |
| Difficult to reverse | 1 | 4 | 13 | 5 | 23 |
| Irreversible | 1 | 7 | 7 | 5 | 20 |
Describes the intervention as the article scopes it, and assumes it was delivered as intended. Reversing an effect is not the same as undoing its consequences. Only technologies and interventions carry the axis — 83 of 205 articles. A concept has nothing to undo.
Two failure modes dominate coverage of this field, and the scale catches both. The first is treating a TRL 3 result as if it were a TRL 8 product — the mouse-lived-longer headline. The second is the reverse: dismissing a TRL 9 technology as science fiction because its category sounds futuristic. Cochlear implants have been routine for decades.
The valley in the middle is real. Most attrition happens between TRL 4 and TRL 7, where a thing that works in a controlled setting meets a body that was not consulted. Look at how few articles here sit at 5, 6, and 7 relative to the crowd at 2 and 3, and you have the shape of the whole field: plenty of ideas, a bottleneck at translation, and a small set of things that made it through.
Readiness and evidence are separate axes on purpose. A technology can be at TRL 7 and still contested on whether it does what its proponents claim, because trials can be well-run and still return a null result.
Grades the specific application this article describes, not every use of the underlying platform. A technique can be routine in one tissue and speculative in another. Assignments are editorial judgements about the most advanced credible demonstration, not certifications. Where a technology spans levels across applications, the article takes the level of its leading clinical use.
Readiness measures how far something has been built and demonstrated. It is not a measure of how well it works, and it is silent on whether the demonstration was in a person or an animal.