 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 to model parameters in a coherent manner. The coherence criterion may be viewed as a conjunction of two sub-criteria: (i) coherence of model assumptions with relevant background theories or other substantive presuppositions about the quantity being measured; and (ii) objectivity, i.e., the mutual consistency of measurement outcomes across different measuring instruments, environments and  models[18]  (Frigerio et al. 2010; Tal 2017a; Teller 2018). The first sub-criterion is meant to ensure that the intended quantity is being measured, while the second sub-criterion is meant to ensure that measurement outcomes can be reasonably attributed to the measured object rather than to some artifact of the measuring instrument, environment or model. Taken together, these two requirements ensure that measurement outcomes remain valid independently of the specific assumptions involved in their production, and hence that the context-dependence of measurement outcomes does not threaten their general applicability.