RSS Evaluative Reporting

Question 1

What type of report provides an assessment of the strengths to be attached to findings?

Answer 1

Evaluative

Question 2

Synonymous with transposing the conditional - is this type of fallacy?

Answer 2

Prosecutors fallacy

Question 3

What is probability?

Answer 3

is a measurment of that event will occur
* quantified as a number between 0 and 1
* zero indicates impossibility of the event occuring
* one indicates certainty

Question 4

What are the rules of probability?

Answer 4

1. when an event cannot occur the probability will be 0
2. when an event is certain to occur the probability is 1
3. the sum of the probabilies of all the outcomes in the sample is 1
4. the probability that an even will not occur is equal to 1 - the probability that the event will occur

Question 5

What are the two factors that are required to determine probability?

Answer 5

1. E the event whose probability is being considered
2. I the information available to the assessor when the probability of E is being considered

Question 6

What are the two things that probability can be?

Answer 6

1. Objective: a logical measure of chance where everyone would be expected to agree to the value of the relevant probability
2. Subjective: measuring the strength of a persons belief in a particular proposition

Question 7

What is the notation that shows the probability that the accused is guilty given the evidence?

Answer 7

p (G|E)

Question 8

What is the notation for the probability that the accused is innocent given the evidence introduced?

Answer 8

p (I|E)

Question 9

What is Bayes Theorem?

Answer 9

Posterior odds = likelihood ratio x prior odds

Question 10

What is the posterior odds in terms of probabilities?

Answer 10

Pr(Hp|Evidence) / Pr(Hd|Evidence)

Question 11

Case of Lucia De Berk

Answer 11

• example of prosecutors fallacy
• statistician said the odds were 342 million to 1 that it was a coincidence she had been duty when all incidents occurred
• some deaths she wasnt actually present for
• statistic was recaculated and she was acquitted

Question 12

What are the two types of samples?

Answer 12

1. recovered or questioned samples (unknown origin)
2. control or reference sample of known origin

Question 13

What is relative frequency?

Answer 13

Calculated against the items observed over a period of time or from all DNA profiles in a defined population

Question 14

How are the figures in the likelihood ratio formed?

Answer 14

• extensive surverys, databases or experimention
• personal experiences and previous casework

Question 15

What are the two probabilities or likelihoods?

Answer 15

1. the likelihood of the evidence if the prosecutions proposition is true
2. the likelihood of the evidence if the defence proposition is true

Question 16

What does the relative value of the two likelihoods provide?

Answer 16

• a measure of the meaning
• probative value of evidence
• represented as the likelihood ratio

Question 17

What are the alternative names for prior odds?

Answer 17

• background rates
• base rate

Question 18

What case demonstrates base rate level?

Answer 18

Benn and Benn
* base rate levels of drugs on banknotes

Question 19

What is base rate fallacy?

Answer 19

making a probability judgement based on conditional probabilities without taking into account the effect of prior odds

Question 20

The probability of guilt given the evidence and vice versa is an example of what odds?

Answer 20

Posterior

Question 21

Frequencies can be both relative and?

Answer 21

Absolute

Question 22

A logical measure of chance is referred to as this type of probability?

Answer 22

objective

Question 23

What are three ways statistics can be expressed as?

Answer 23

1. percentage
2. proportion (relative frequency)
3. probability/likelihood

Question 24

Case of Reed and Reed (2009)

Answer 24

• shows issue around transfer
• plastic from two separate knife handles were found next the victims body
• cellular material on both pieces of plastic matched Reed and Reed

Question 25

Give examples of where DNA samples can originate?

Answer 25

* bone * hair * vomit * faeces * skin flakes * biological fluid

Question 26

What three biological fluids are not detectable by visual examination or presumptive tests?

Answer 26

* sweat * skin cells * vaginal secretions

Question 27

What was directed towards challenging the admissibility of evidence given by Valerie Tomlinson in the case of Reed and Reed?

Answer 27

the manner and timing of the transfer of the appelants DNA

Question 28

Valerie Tomlinson issues

Answer 28

* her opinion was that the DNA transferred through primary transfer * failed to account for the fact only a fragment of each handle was found * did not consider the possibility that there might have been cellular material from others on the rest of the handle or blade

Question 29

What issues was said about professor jamieson in the Reed & Reed?

Answer 29

* private commercial organisation * not accredited by UKAS or any other body in England, Wales or Scotland * experience in interpretating DNA profiles is limited * doesnt conduct lab research * not qualified to make a scene of crime investigation

Question 30

Issues with source level propositions

Answer 30

* do not say anything about how evidence came to be at the scene * dont take into account variables such as quantity, position or distribution * can only address whether or not evidence came from a particular source * require little in the way of circumstantial information

Question 31

What is the ultimate issue which the court must deal with?

Answer 31

Offence level statements make conclusions about criminal responsibility and liability

Question 32

Why should experts not testify to propositions at offence level?

Answer 32

* they involve factual and moral judgement that forensic scientists are not juridictionally competent to make * was harm caused unlawfully

Question 33

What words should be used for reporting the narrative?

Answer 33

* cannot be excluded * consistent with * could have come from * could have originated from

Question 34

What is relative frequency?

Answer 34

* empirical probability * proportion of times that a particular event occurs relative to the total number of observations

Question 35

If the relative frequency of the DNA in the general population is 1 in 1000, what is the probability that a suspect is guilty?

Answer 35

1- 1/1000 = 999/1000

Question 36

Where the scientist can say that the source of DNA came from a particular body fluid. What terminal do we use here?

Answer 36

attributable

Question 37

The non-DNA evidence, used in the case of Reed and Reed locating the offenders?

Answer 37

cell site analysis

Question 38

What is the semantic scale that is sometimes used for the likelihood ratio?

Answer 38

1. moderate support 2. weak support 3. strong support 4. very strong support

Question 39

What are the posterior odds equal to when they are in favour of the prosecution proposition?

Answer 39

the product of the ratio of the probability of the evidence if the prosecutions proposition is true, to the probability of the evidence, if the defence is true and the prior odds in favour of the prosecution proposition