Standard error of prediction (SEP) should not be greater than 1.3 times the standard error of calibration (SEC)

"As recommended by the instrument/software vendor, generally, standard error of prediction (SEP) should not be greater than 1.3 times the standard error of calibration (SEC) and the bias should not be greater than 0.6 times the SEC (50). High values of SEP or bias indicate that the errors are significantly larger for the new
cross-validation samples and that the calibration data may not include all the necessary variability or be over fit."

(P. 265 in: Stuart L. Cantor, Stephen W. Hoag, Christopher D. Ellison, Mansoor A. Khan, and Robbe C. Lyon (2011). NIR Spectroscopy Applications in the Development of a Compacted Multiparticulate System for Modified Release. AAPS PharmSciTech, Vol. 12, No. 1, March 2011)

"A large difference indicates that too many latent variables are used in the model and noise is modeled. "

(P.318

In Li et al., (2007) Nondestructive measurement and fingerprint analysis of soluble solid content of tea soft drink based on Vis/NIR spectroscopy, J. of Food Eng, 82, 316-323.)