Despite similarities between Material Flow Analysis (MFA) and Input-Output Analysis (IOA), integration between the two has so far remained limited. This thesis conducts a critical comparison eleven to better undistinct data types used in MFA and IOA, to better understand what obstacles hold back integration. Unlike earlier studies, which focused on similarities in purpose and data structure, the emphasis of this thesis is on terminology and conceptual interpretation, which until now have not been clearly reviewed and articulated.

Key contributions of this thesis include conceptual clarification and recommendations on the use of terminology, as well as a method-neutral conceptual framework to use where conventional terminology proved insufficiently precise. Together, these strategies improve conceptual clarity and precision, reduce misunderstandings when discussing multiple data types simultaneiously, and make it easier to discuss conceptual similarities between data types.

The critical comparison, conducted with help of a novel conceptual mapping approach, finds that differences between MFA data, Supply-Use Tables (SUTs), Input-Output Tables (IOTs), and their subtypes stem from four key sources: (i) a lack of terminological alignment between MFA and IOA; (ii) misalignment of system boundaries and disaggregation schemes; (iii) varying units-of-account; and (iv) the one-to-one correspondence requirement between products and industries in IOTs. Only the latter two relate to fundamental characteristics of data types. Misalginment of terminology, system boundaries and disaggregation schemes could in principle be addressed by revising or adapting established conventions.

From these findings, the conclusion is drawn that no insurmountable barriers stand in the way of integration or unification MFA data with Physical Supply-Use Tables (PSUTs). Because the System of National Accounts (SNA) and System of Environmental-Economic Accounting (SEEA) are already well-established and guarantee alignment with a broad range of other economic statistics, the most promising route to integration seems to be for MFA practitioners to seek alignment with these frameworks and/or adopt a PSUT format for storing data. This would increase the comparability and reusability of material stock and flow data, while also strenghtening the case for systematic data collection.

Finally, this thesis emphasizes that differences between monetary and physical data cannot be overcome with simple unit conversions, even when using sophisticated models such as WIO-MFA. It therefore points to multilayer Hybrid Supply-Use Tables (HSUTs) as a promising approach to integrate monetary and physical data for comprehensive analyses of socio-economic metabolism.