Comparing two analytical methods: minimal standards in forensic toxicology derived from information theory

Area of Science:

• Forensic Science
• Information Theory
• Analytical Chemistry

Background:

• New analytical instrumentation and techniques are frequently adopted in casework without thorough validation against established procedures.
• Assessing the reliability and comparative performance of novel methods is crucial for maintaining casework integrity.

Purpose of the Study:

• To introduce information theory as a mathematical framework for evaluating the identification power of analytical procedures.
• To provide methods for comparing new techniques with accepted analytical methods based on relative informational power.
• To guide analysts in estimating the potential of novel techniques to meet accepted standards and identify areas for improvement.

Main Methods:

• Utilizing principles of information theory to calculate and compare the "informational power" of different analytical procedures.
• Developing a framework for estimating the confidence in analysis provided by new versus established methods.
• Outlining procedures for analysts to assess novel techniques against existing benchmarks.

Main Results:

• Information theory offers a quantitative approach to estimate the identification power of analytical methods.
• Relative informational power can predict whether a new method offers greater or lesser confidence than an accepted method.
• The outlined procedures enable analysts to gauge the potential equivalence of novel techniques to accepted standards.

Conclusions:

• Information theory provides a valuable tool for the preliminary assessment of new analytical techniques in forensic casework.
• While information theory can help dismiss inadequate methods early, full procedural verification is still necessary to confirm a technique's suitability for a specific task.