Evaluation and Interpretation of Forensic Evidence

Understanding Evidence Context

• Evidence does not stand alone: its value and relevance are often determined by the context of the crime under investigation.
• Forensics experts must therefore understand the circumstances of the crime, including victim profiles, suspect information, and crime scene data.
• This broader picture can provide key insights into how the evidence fits into the crime narrative, revealing potential motives, relationships, or patterns of behaviour.

Evaluating Different Types of Evidence

• Different types of evidence offer diverse information, from the physical appearance of blood splatter to the microscopic properties of a fibre.
• Specialists such as serologists, trace evidence analysts, and ballistics experts are often needed to properly evaluate the intricate details of this evidence.
• These experts can, for example, determine whether a blood pattern is consistent with a struggle, or identify the source of an unknown fibre.

Critical Approach to Evidence Interpretation

• Interpreting forensic evidence often involves using logical reasoning and objective judgement.
• Investigators should constantly question their assumptions, approach each piece of evidence with healthy scepticism, and consider multiple explanations.
• They should also be aware of cognitive biases that might affect their judgement, such as confirmation bias or tunnel vision.

Reliability and Limitations of Evidence

• All types of evidence have their limitations and uncertainties, and these must be considered during interpretation.
• For instance, DNA evidence is often seen as conclusive, but it can also be contaminated or misinterpreted. It's also not infallible: two people can share the same DNA profile in every one billion people.
• Solid interpretation therefore involves understanding these constraints, assessing the reliability of the evidence, and considering its weight in the context of the overall investigation.

Presenting Forensic Findings

• Forensic experts often have to communicate their findings to non-experts, like police officers, lawyers, juries, or even the public.
• Therefore, they have to be able to explain complex concepts simply and clearly, ensuring that the significance and limitations of the findings are well understood.
• Their assessments need to be both detailed and concise, and supported by the objective facts of the case.

Importance of Peer Review

• Peer review by other forensics professionals is a critical part of the evaluation process.
• This kind of review ensures the quality and accuracy of the forensic work, reduces the likelihood of errors, and ensures that the interpretations made are supported by the evidence.
• If an expert’s interpretations are not supported during peer review, they may need to be revised or discarded. This underlines the essential role of close scrutiny and ongoing dialogue in forensic work.