Improving uncertainty in Widmark equation calculations: alcohol volume, strength and density

Peter D. Maskell*, R. Alex Speers, Dawn L. Maskell

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)
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    The Widmark equation is probably the most commonly used calculation for medicolegal purposes. Recently the National Research Council (USA) and the Forensic Science Regulator (UK) have called for the uncertainty of all results to be given with all forensic measurements and calculations. To improve the uncertainty of measurement of results from Widmark calculations we have concentrated on the uncertainties of measurement involved in the calculation of alcohol, that of the volume of alcohol, the concentration of alcohol and the density of alcohol as previous studies have investigated some of the other factors involved . Using experimental studies, the scientific literature and legal statutes, we have determined revised and improved uncertainties of the concentration of ethanol for Widmark calculations for both the USA and UK. Based on the calculations that we have performed we recommend the use of Monte Carlo Simulation for the determination of uncertainty of measurement for Widmark Calculations.
    Original languageEnglish
    Pages (from-to)321-330
    Number of pages10
    JournalScience & Justice
    Issue number5
    Early online date16 May 2017
    Publication statusPublished - Sep 2017


    • Widmark
    • Alcohol technical defence
    • Back calculation
    • Uncertainty of measurement


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