This guidance for the interpretation of isotope ratio data has drawn together the experiences of institutional members of the FIRMS Network working as forensic practitioners applying isotope ratio analysis within various jurisdictions worldwide into single, generally applicable guidance document.

As with the Good Practice Guide for Isotope Ratio Mass Spectrometry, this document is aimed at providing both experienced forensic practitioners and relative newcomers a helping hand, interpreting rather than obtaining isotope ratio data in a forensic context.

Interpretation is undoubtedly a complex subject which has been simplified in this guide. The FIRMS Network welcomes any and all feedback, whether complimentary or critical so that future editions may be improved.

The guide was produced by members of the Forensic Isotope Ratio Mass Spectrometry (FIRMS) Network. If you have any comments please contact the FIRMS Network via gpg@forensic-isotopes.org.