Forensic Science and Technology
Scope and limits
Forensic science supports investigations by analyzing physical and digital traces. Candidates should understand the main categories: fingerprint, DNA, trace evidence, toxicology, questioned documents, ballistics, and digital forensics. Each has capabilities and limits, and none is infallible.
Key concepts
Know the difference between identification and individualization, the meaning of a match, and the importance of validated methods and laboratory quality controls. Understand that forensic results are probabilistic and that interpretation depends on context. Digital forensics involves acquisition, preservation, examination, analysis, and reporting, with integrity assured through hashing and documented procedures.
Traps in questions
Frequent traps include treating a partial match as identification, confusing absence of evidence with evidence of absence, and assuming that a tool's output is an expert conclusion. Another trap is ignoring contamination and transfer issues.
Rule of thumb
Use the "question, method, limitation" rule: for any forensic result, state the question it addresses, the method used, and the limitations of that method.
Worked example
A DNA profile matches a suspect. The investigator reports the match and the statistical weight, notes that DNA transfer can occur without direct contact, and avoids asserting how the DNA was deposited. The result supports a hypothesis but does not alone establish conduct.