Measurement outcomes that satisfy coherence and objectivity remain valid independently of the specific assumptions involved in their production.

Model-based accounts diverge from empiricist interpretations of measurement theory in that they do not require relations among measurement outcomes to be isomorphic or homomorphic to observable relations among the items being measured (Mari 2000). Indeed, according to model-based accounts relations among measured objects need not be observable at all prior to their measurement (Frigerio et al. 2010: 125). Instead, the key normative requirement of model-based accounts is that values be assigned t