Some Thoughts on Validity


External validity refers to the extent to which a specific finding from an investigation or analytical process can be generalized beyond the context of the specific investigation or analytical process. For regulatory purposes such as the manufacture of drugs and therapeutic biologicals, validity can be considered to be demonstration of the ability to reproducible repeat the process and/or assay. The validation process is the process by which an organization can demonstrate that the process is reproducible and, therefore, the process is valid.  In the case of assay validation; “Method Validation: The process of demonstrating or confirming that a method is suitable for its intended purpose. Validation includes demonstrating performance characteristics such as accuracy, precision, specificity, limit of detection, limit of quantitation, linearity, range, ruggedness and robustness.” Regulatory agencies such as the International Council for Harmonisation (ICH) and the  Food and Drug Administration (FDA) have detailed requirements for the validation of analytical procedures (1,2) and manufacturing procedures (3)  In the case of manufacturing, validation is defined as  “A documented program that provides a high degree of assurance that a specific process, method, or system will consistently produce a result meeting pre-determined acceptance criteria(3). Validation is of importance in all fields of investigation  including the social sciences (4).


1.  Guidelines for the Validation of Chemical Methods for the FDA FVM Program, 2nd Ed., Food and Drug Administration, Office of Foods and Veterinary Medicine, Bethesda, Maryland, USA, 2015.
2.  Validation of Analytical Procedures: Text and Methodology, Q2(R1), ICH, Geneva, Switzerland 2014.
3.   Good Manufacturing Practice Guide for Active Phamaceutical Ingredients, Q7, Geneva, Switzerland, 2000
4.  Taylor, C.S., Validity and Validation, Oxford University Press, New York, New York, USA , 2013;