Evaluative Conclusion
Definition
A forensic opinion that addresses the weight of the evidence, typically expressed as an LR or a verbal equivalent. Distinct from a finding (what was observed) or an identification (a categorical claim). The evaluative conclusion places the observed findings in a probabilistic framework comparing competing hypotheses.
- Typical expression
- Likelihood ratio or verbal equivalent
- Distinct from
- A finding and a categorical identification
- Framework
- Comparing competing hypotheses
- Function
- States the weight the evidence carries
Common questions
How is an evaluative conclusion different from a finding?+
A finding describes what the examiner directly observed, such as a specific pattern or measurement, while an evaluative conclusion goes further to state how much that observation supports one proposed explanation over a competing one.
Why do evaluative conclusions require stating two competing hypotheses?+
A likelihood ratio is only meaningful relative to alternatives, so the conclusion must specify what is being compared, for example that the mark came from a specific source versus an unknown other source, otherwise the probabilistic weight has no defined reference point.
Is a categorical identification a stronger claim than an evaluative conclusion?+
A categorical identification asserts certainty rather than expressing a graded weight, so it is a different type of claim rather than simply a stronger version of an evaluative conclusion, and many forensic disciplines are moving toward evaluative reporting specifically to avoid overstated categorical claims.
Related terms
- ENFSI Guideline for Evaluative Reporting
- A consensus guidance document from the European Network of Forensic Science Institutes that defines how member laboratories should express evaluative opinions. It...
- 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...
- Source-Level Hypothesis
- A proposition about who or what produced a trace, for example 'this glass came from the broken window at the crime scene'...
- UK Forensic Science Regulator (FSR)
- The statutory body in England and Wales responsible for setting and monitoring quality standards in forensic science. The FSR has published codes...
- Verbal Scale
- The ENFSI translation of numerical likelihood ratios into courtroom language: very strong support (LR over 10,000), strong support (LR 1,000-10,000), moderate support...