Our new article in the Journal of Forensic Science describes a simple approach for quantifying the spread/diversity of a set of measurements, and discusses how we can use this metric to evaluate how well various measurement techniques work towards the broader problem of identifying fentanyl analogs. This work was done in collaboration with Edward Erisman, Anthony Kearsley, Yuxue Liang, Edward Sisco and William Wallace from the National Institute of Standards and Technology (Gaithersburg, USA).