Source-level proposition
Definition
A proposition about the origin of material. Example: 'The DNA profile originated from the suspect' versus 'The DNA profile originated from an unknown person.' Source-level propositions are often not the most legally relevant question, which is usually how the material came to be where it was found.
Related terms
- Activity-level proposition
- A proposition about what happened. Example: 'The suspect handled the knife' versus 'The suspect never handled the knife.' Activity-level propositions require the...
- 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...
- Offence-level proposition
- A proposition about guilt. Example: 'The suspect committed the assault' versus 'The suspect did not commit the assault.' Forensic scientists must not...
- Prosecutor's fallacy
- The error of treating the RMP (or its reciprocal) as the probability that the defendant is innocent, or as the probability that...
- Verbal equivalent scale
- A standardised mapping from LR ranges to descriptive phrases, such as the ENFSI scale: LR 10 to 100 corresponds to 'moderate support',...
Explained in
- Writing Evaluative Statements in Forensic ReportsA proposition about the origin of material. Example: 'The DNA profile originated from the suspect' versus 'The DNA profile originated from an unknown person.'...