Techniques for evaluating the differences in consumption-based accounts: a comparative evaluation of Eora, GTAP and WIOD

The Eora, GTAP and WIOD multiregional input-output (MRIO) databases calculate different national level CO2 consumption-based accounts (CBA). If these outcomes are to be used as evidence in climate policy, analysts need to be confident as to the accuracy of the databases and to understand why the results differ. This thesis explores the different data sources, database structures and construction techniques used to build Eora, GTAP and WIOD. Analytical techniques, such as matrix difference statistics, structural decomposition analysis and structural path decomposition are used to quantify the nature of the difference and determine the cause of outcome difference. To make meaningful comparisons between the three MRIO databases, each is mapped to a consistent classification system comprising 40 countries and 17 sectors. The effect of this aggregation is shown to be fairly minimal, giving confidence that the aggregated versions of each database reflect the full-sized versions. This study finds that the main cause of difference in the CO2 CBA as calculated by different MRIO databases lies in the different emissions extension vectors used. Not only is the global emissions total different, but the distribution of emissions by industrial and the household sector differs depending on whether the particular database takes the territorial or residence principle to emissions allocation. The effect of differing global totals can be observed in the national CO2 CBA calculated for the same country being different in each database. The effect of the territorial or residence principle is evident when results are compared at the supply chain level. At this level of detail, it is also possible to quantify the effect of differing construction techniques used to populate data in the economic matrices. The thesis concludes by making recommendations as to how future MRIO databases could be constructed in an accurate and consistent manner and how they should be used in policy in light of the findings.