The test set for each simulation method (ChemDraw ® , DFT, and library) assessed the influence of error in the predicted isotropic shifts of the resonances in the component spectra on the ability to fit the component spectra to the composite spectrum. To simulate a case in which the candidate compounds are known, but the predicted shifts have some error, each component spectrum from the artificial data set was copied, and the isotropic chemical shifts of each resonance were jittered. A point was sampled from a Gaussian distribution centered at 0 with a standard deviation dependent on the method of testing (σ ≈ 0.4 ppm for ChemDraw, 0.1 ppm for the DFT method herein, and 0.01 ppm for spectra reported in chemical libraries), and this point was added to the base isotropic shift value to introduce artificial error. The jittered component spectra were then fit to the composite spectrum to identify the weights of each component spectrum, despite the errors in chemical shift. Each test was repeated 15 times, each time generating a new, random set of spectra, and the results were averaged. The results for the Benchmarks 1 and 2 are summarized in Table and Benchmark 3 is summarized in Table .