A statistical approach to modeling the underground economy in South Africa

Abstract Aim/purpose – The underground economy is a major challenge across the world affecting both developed and developing economies. South Africa is no exception to this phenomenon and has lost billions of rands due to the underground economy. The aim of this study is to estimate the size of the underground economy in South Africa. Design/methodology/approach – The study used quarterly time series data from 2000 to 2020 and employed the Currency Demand Approach (CDA) for modeling the underground economy. Findings – The model results revealed that the underground economy is positively influenced by unemployment rate, tax burden, and social benefits granted by the government, however it is negatively influenced by Nominal Gross Domestic Product (NGDP), deposit interest rate, and self-employment rate. Furthermore, the study showed that there was a distinct growth of the underground economy, from 23.9% of GDP in 2003 to 34.5% of GDP in 2019. On average, the underground economy represented 28.8% of GDP for the period 2003 to 2020. Research implications/limitations – This model can be used in conjunction with other models to observe the trend in the South African underground economic activities. The South African government should take note of the spiraling growth of this economy and come up with measures to curb this growth to protect the formal economy. Originality/value/contribution – This study makes a significant contribution to the body of knowledge in this research area and provides much needed insights into the magnitude of the underground economy and the extent of tax evasion in South Africa.