Guidance on Bias

Question 1

What is the Forensic Science Regulator’s Code of Practice?

Answer 1

• Forensic Science Providers and Practitioners must act with:
  
  • Honesty
  • Integrity
  • Objectivity
  • Impartiality

Question 2

What is expectation bias and confirmation bias?

Answer 2

Both are forms of cognitive bias.

• Expectation bias:
  
  • Also known as experimenter’s bias
  • Where the expectation of what an individual will find affects what is actually found.
• Confirmation bias:
  
  • Closely related to expectation bias.
  • People test hypotheses by looking for confirming evidence rather than conflicting evidence.

Question 3

What are anchoring effects?

Answer 3

A type of cognitive bias.

• Closely related to experimental and confirmatory biases.
• Occur when an individual relies too heavily on an initial piece of information when making subsequent judgements, which are then interpreted on the basis of the anchor

Question 4

What are contextual bias and role effects?

Answer 4

Contextual bias: Where someone has other information aside from that being considered which influences the outcome of the consideration.

Role Effects are where scientists identify themselves within adversarial judicial systems as part of the prosecution or defence. This may introduce subconscious bias which may influence decisions - particularly when ambiguity exists.

Question 5

What are motivational bias and reconstructive effects?

Answer 5

Motivation bias occurs where motivational influence on decision making results in information consistent with a favoured conclusion tending to be subject to a lower level of scrutiny than information that may have supported a less-favoured outcome.

Reconstructive effects can occur when people rely on memory rather than taking contemporaneous notes. People tend to fill in the gaps with what they believe should have happened and so may be influenced by protocol requirements.

Question 6

What is ACE-V?

Answer 6

• ACE-V is the most commonly accepted approach to fingerprint comparison in the UK and USA.
• The sequence of working is:

1. An examiner analyses a mark.
2. The examiner then compares the mark with a known print.
3. The examiner evaluates what they have seen and reaches a decision; and
4. The results are subject to verification by one/more examiners.

Question 7

What is a proxy proposition?

Answer 7

A proxy proposition is where the defendant gives a no comment interview. This means that the forensic scientist is required to make their own, uninformed suppositions about appropriate defence hypotheses; the proxy proposition.

Question 8

How is Linear Sequential Masking implemented to minimise bias?

Answer 8

• LSU does not prevent exposure to biasing relevant information.
• However it does ensure that the biasing information is presented as late as possible in the examination process and only where necessary.
• The forensic examiner must first examine the evidence from the crime scene (Level 1) before being exposed to known reference material (Level 2)