Answers are grounded in this paper and cite their sources.
In this paper, the main focus lies on the informal economy and on work in the shadow. The most influential factors on the informal economy are tax policies and state regulation. The size of the informal economy was decreasing over the period 1999 to 2007, from 34.0% to 31.2% for 161 countries (unweighted average). Furthermore, economic opportunities, taxes and regulations, the general situation on the labor market, and unemployment are crucial for an understanding of the dynamics of the shadow labor force. In contrast with the decrease of the informal economy (value added figures), the informal economy labor force increased for most countries over the period 1999 to 2007.
No takes yet. Share an insight, caveat, or question.
Friedrich Schneider (2015) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: