Table 4.
Approximate probability scale recommended for harmonised use in EFSA to express uncertainty about questions or quantities of interest
| Probability term | Subjective probability range | Additional options | |
|---|---|---|---|
| Almost certain | 99–100% | More likely than not: > 50% |
Unable to give any probability: range is 0–100% Report as ‘inconclusive’, ‘cannot conclude’, or ‘unknown’ |
| Extremely likely | 95–99% | ||
| Very likely | 90–95% | ||
| Likely | 66–90% | ||
| About as likely as not | 33–66% | ||
| Unlikely | 10–33% | ||
| Very unlikely | 5–10% | ||
| Extremely unlikely | 1–5% | ||
| Almost impossible | 0–1% | ||
This table was adapted from a similar scale used by the Intergovernmental Panel on Climate Change. Additional details and guidance on use can be found in EFSA Scientific Committee (2018b).