Simulating personal income tax in South Africa using administrative data and survey data: A comparison of PITMOD and SAMOD for tax year 2018

In this paper we explore South Africa’s personal income tax system using two microsimulation models. The first, SAMOD, simulates personal income tax and social benefits using a dataset derived from the nationally representative National Income Dynamics Study survey. The second, PITMOD, simulates the personal income tax system and is underpinned by a dataset comprising a full extract of anonymized individual-level administrative tax data especially constructed for this purpose. The two models have a common framework in the form of the EUROMOD microsimulation software and interface, and have a common policy timepoint of 1 March 2017. Discrepancies between the simulated personal income tax generated by each model are explored in order to better understand the strengths and weaknesses of the two models.