Spatial data quality impacts on the efficiency of the property tax system: The case of construction land fees

Spatial data are directly linked to spatial planning, and to spatial management in general, including the property tax system. Spatial data quality impacts the efficiency of the property tax system, as well as its equity and reasonability. This article presents a methodological approach to analysing the quality of spatial databases managed by municipalities for assessing construction land fees. Adjusted Jaccard and Czekanowski indices were defined and applied for data quality analysis because they are applicable in cases in which differences between the data compared amount to less than 5%. The indices were used to establish the level of matching for areas of buildings and the unbuilt construction land in the municipal construction land fee assessment databases and in the real estate register. Based on an analysis of the completeness, logical consistency, and thematic accuracy of municipal construction land fee assessment databases, municipal databases were updated. Modifications to the municipal databases were analysed following updating in terms of the number of persons subject to construction land fee payment and the construction land fee amount payable. The results of the first study of this type have been obtained on a small sample, but the methodology is also applicable for analysis on a large sample or in all Slovenian municipalities. As such, the analysis may be of help to experts at municipal offices, spatial planners, and decision-makers in taxation policies.