Case Assessment and Intepretation

Question 1

What are the hierarchy of propositions?

Answer 1

Source: Infer to where the evidence came from. E.g. did the semen originate from the suspect?

Activity: How did the evidence arise? E.g. Has the suspect had sexual intercourse with the complainant?

Offence: This addresses whether the suspect committed an offence, for example; did the suspect rape the complainant?

Question 2

What are the different types of hypotheses used by forensic scientists when calculating a likelihood ratio?

Answer 2

Prosecution Hypothesis: The evidence originated from the suspect and they committed the crime.

Defence hypothesis: The evidence did originate from the suspect, although appeared in an innocent manner, or the evidence did not originate from the suspect at all.

Question 3

What is a likelihood ratio?

Answer 3

The probability (Pr) of the Evidence (E) given (A) the Prosecution hypothesis and the Information (I)

divided by

(B) the defence hypothesis and the Information I