Facet - G-String-Legacy/GS_MV GitHub Wiki
In 'generalizability' jargon design factors are called 'Facets'. There are three types of facets:
Facet of Differentiation
In any analysis of generalizability there has to be exactly one facet of differentiation - the subjects being evaluated.
Facets of Stratification
Each subject may be classified further for the analysis e.g. by origin, age, gender etc.
Facets of Generalization
Performance may be classified further by aspects of the task, or by individual performance raters.