Figure shows the fraction of occurrence, 𝐹(𝑙), for observed loss peak, 𝑙, in mass spectra of organic molecules with nominal molecular mass between 50 Da and 500 Da contained in the NIST17 Main Library. Note that any 𝑙 = 0 is indicative of a molecular ion peak, and 𝑙 < 0 represent peaks of isotopes of molecular ions. All 𝑙 > 0 are associated with neutral losses peaks or isotopes thereof. A loss peak is defined as illogical if its fraction of occurrence in the NIST17 Main Library is less than or equal to a selected threshold fraction, say 𝜏 % .