ENFSI Evaluative Standard
Definition
The European Network of Forensic Science Institutes 'Standard for Formulation of Evaluative Forensic Science Expert Opinions' (2015/2016), which requires examiners to reason explicitly about two competing hypotheses and to express their opinion as support for one hypothesis relative to the other, using a verbal LR scale anchored to numerical intervals.
- Document
- ENFSI Standard for Formulation of Evaluative Forensic Science Expert Opinions
- Years
- 2015 and 2016
- Core requirement
- Explicit reasoning under two competing hypotheses
- Output format
- Verbal LR scale anchored to numerical intervals
Common questions
How does this standard differ from the separate ENFSI evaluative reporting guideline?+
They describe the same underlying two-hypothesis, likelihood-ratio approach; the Standard sets the formal minimum requirements an opinion must meet, while the broader Guideline document provides the fuller explanatory and procedural guidance for implementing it.
Why anchor the verbal scale to numerical LR intervals rather than leaving it purely descriptive?+
Anchoring keeps wording like 'strong support' tied to a defined numerical range, which stops examiners drifting toward stronger or weaker language than the underlying statistics justify and keeps testimony consistent across cases and laboratories.
Related terms
- Courtroom-Language Translation Problem
- The empirically documented gap between what forensic verbal conclusion terms (such as 'strong probability') are intended to convey by examiners and what...
- Elimination (SWGDOC)
- The most definitive negative conclusion on the SWGDOC scale, meaning fundamental differences in writing habits that cannot be attributed to disguise, natural...
- Foundational Validity as Applied
- PCAST's standard requiring that a forensic discipline be validated through black-box studies measuring real-examiner error rates under realistic conditions, not just laboratory...
- Identification (SWGDOC)
- The most positive conclusion on the SWGDOC scale, meaning the examiner has found individualising agreement in all significant habitual writing characteristics, with...
- Likelihood Ratio (LR)
- The ratio of two conditional probabilities: the probability of the observed evidence given the prosecution's hypothesis (same source), divided by the probability...
- No Conclusion (SWGDOC Position 5)
- The midpoint of the SWGDOC scale, indicating that the evidence is equally consistent with a common source or different sources. It is...
- PCAST 2016 Report
- The President's Council of Advisors on Science and Technology 2016 report 'Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods,'...
- Population-Frequency Anchoring
- The practice of grounding a conclusion about feature rarity in empirically measured frequency data for those features in the relevant writing population,...
- SWGDOC Nine-Point Scale
- The conclusion scale developed by the Scientific Working Group for Forensic Document Examination, running from 'identification' (most positive) through 'no conclusion' (midpoint)...