Distinguishing between specialties

There is no conventional method for dividing the forensic community into specialist groups. We have worked hard to describe what practitioners in the different specialties do for the purpose of the register. Many of the specialties divide further into subspecialties, so that we can identify the precise areas in which a practitioner is competent.

To help us define specialties clearly and design suitable registration schemes, we have grouped the specialties into three sectors. Each sector is overseen by an assessment panel. The boundaries between these sectors are not hard and fast. Some specialties - such as the analysis of fires, explosions or transport incidents - actually straddle them. In such cases we tend to use the terms investigation (sometimes examination) and evaluation to distinguish between the specialties.

The investigative role focuses on speculating about explanations for scientific findings, ranked if possible, to provide direction to the investigation of a crime. The issues considered are more likely to be centred on the crime (scene and offender). The practitioner applies their expertise and their in-depth technical knowledge to help the investigation, make inferences and answer questions.

This type of practitioner provides direction to the investigation by making observations, classifying materials, suggesting and ranking explanations and eliminating possibilities. They can also appear in court to provide evidence of their findings and use their technical knowledge and experience to answer questions and provide explanations.

The evaluative role involves interpreting scientific findings of at least two alternative hypotheses (usually prosecution and defence) and weighing these findings impartially against each other. The evaluator is allowed to provide evidence of opinion to the court. The issues considered in this case are more likely to be centred on the defendant.

The evaluator applies their expertise to help the judicial process, enabling the court to draw the correct inferences and answer the questions raised. They deal with pairs of given propositions, evaluating the observations against these, and corroborating the version of events provided by either the prosecution or the defence.

Usually, those forensic practitioners involved in the investigative element of a case will not also be involved in evaluating the evidence. Practitioners who provide evaluative interpretation will often use both investigative and evaluative skills at different stages of a case.