Having a calibration programme is just part of the process to towards generating a valid result. It provides assurance that suitable equipment is being used and that results are traceable to SI units. Validation however is the process of providing objective evidence that a method can perform consistently to meet specified requirements that are adequate for the intended use of method. Requirements could be that a specific (low enough) detection level or high enough accuracy can be achieved. ISO 17025 also requires that a laboratory monitors and evaluates its performance by comparison with other laboratories, through proficiency testing (PT) or interlaboratory comparisons
All these activities are required to show technical competency.