Propositions (Hp / Hd)
Definition
The two competing hypotheses in evaluative reporting. Hp is the prosecution proposition (for example, the accused is the source of the trace), and Hd is the defence proposition (for example, an unknown person is the source). The likelihood ratio is always calculated with respect to a specific pair of propositions.
Related terms
- Bayes' theorem
- The mathematical rule that relates prior odds, the likelihood ratio, and posterior odds. In the odds form: O(Hp|E) = O(Hp) x LR....
- Evaluative reporting
- A framework for expressing forensic conclusions in terms of the probability of the evidence given the prosecution hypothesis versus the defence hypothesis...
- 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...
- 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...
- Random match probability (RMP)
- The probability that a randomly chosen unrelated person from the relevant population would match the evidence profile by chance. A very small...
Explained in
- How Numbers Enter Forensic ConclusionsThe two competing hypotheses in evaluative reporting. Hp is the prosecution proposition (for example, the accused is the source of the trace), and Hd is the de...