Analytical methods and models require comparison against a reference standard

Secondary methodological support. Fresh scope expanded through printed645 to include actual cross-validation description and database-domain qualification. Do not reproduce the chapter's conflation of PLS regression with PLS discriminant analysis, cross-correlation with cross-validation, or orthogonality with statistical independence. A plotted cluster or reported accuracy is not independent validation; preprocessing and model selection also need validation controls.

The discussion separates routine rapid methods from higher-confidence reference methods and describes calibration and validation for multivariate prediction.

New analytical methods should be rigorously compared with established or official reference methods, and indirect predictions require a calibration model plus an independent test set or cross-validation; method performance and model validity are bounded by the samples and conditions used.

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Section 4.1.5, Development of New Analytical Methods

Fresh text verified PDF659–662 (printed642–645); Table4.1.3 and Figure4.1.2 visually inspected. Reference-method comparison on660, leave-one-out description661 and database-bound prediction662 support this paraphrase. Underlying studies remain research leads. September 28 fresh review now covers all 1185 supplied sheets, including references, appendices, glossary, index and back cover, with443 detail-page inspections. Full reading does not upgrade this secondary passage into independent primary validation.