Verbal LR Scale
Definition
A standardised conversion table from numerical likelihood ratio values to phrases such as 'moderate support' or 'very strong support' for one of the propositions; used in ENFSI-compliant forensic reports to communicate evidential strength to non-specialist courts.
- Framework
- ENFSI Guideline for Evaluative Reporting
- Scale size
- Six standard categories, from limited to extremely strong support
- Function
- Translates a numeric LR into a standard court-friendly phrase
- Scope
- One proposition pair at a time (prosecution vs defence hypothesis)
Common questions
Does the verbal scale change the underlying likelihood ratio?+
No. The numeric LR is calculated first and the phrase is only a fixed translation of that number for the reader, so the scientific reasoning behind the figure is unaffected by which words are chosen to describe it.
Why not just give the court the raw number?+
Courts and juries have repeatedly been shown to misinterpret raw likelihood ratios and probabilities, so ENFSI-aligned labs pair the number with a standardised phrase to reduce misreading while keeping the calculation available for scrutiny.
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