Qualitative analysis: a guide to best practice--forensic science extension

Qualitative analysis is arguably the cornerstone of analysis since what cannot be recognised cannot be quantified. This is especially true in the case of the forensic sciences where, for example, the mere presence of a prohibited, or controlled, substance in an unauthorized setting is indicative of a potential offence. This paper presents a set of principles of good practice in qualitative analysis. The principles are placed in the context of forensic science and extend earlier published guidance.