[1] This prediction was corroborated by the long-term analysis of the economies of Russia and Ukraine (1965–1989) by Treml and Alexeev.
Grossman defines the concept of second economy with a two-prong test, which is the set of economic activities which satisfy at least one of the two conditions: "(a) being directly for private gain (b) being in some significant respect in knowing contravention of existing law.
[4] A significant impact on the economy of the Soviet Union was the system of blat, a network of favors, which allowed people to procure all kinds of goods and services, operating within both official and second Soviet economies and continued to operate in post-Soviet Russia.
[5] Since the early days of the Soviet Union, some authors claim that there has been a tradition to exaggerate the blame of the "black market" for consumer goods shortages, thus effectively shifting the blame off state bureaucrats with their inadequate planning.
[2] During the era of perestroika, the 500 Days program of economic transition mentioned the shadow economy would be an important factor in reforms and predicted that at least 90% of it was to be absorbed by the opening free market.