Often words such as “shadow”, “underground”, “informal”, “undeclared”, “grey”, and “unobserved” are interchangeably used with “hidden” to describe inevitably the same phenomenon but from a different perspective. To clarify – throughout the text “hidden” economy will be used to describe economic activities and practices which are legal (non-criminal) as to their nature but remain undeclared to the authorities unlike “Black” economy that refers to illegal (criminal) activities and practices. Although all these terms, encapsulated by the term “hidden” from here after, carry a negative connotation it must be noted that in the short to mid-term the hidden economy can aid societies and its population to recover from severe economic crisis or transition, for example, from socialist to market based economy. However, in mid to long-term it jeopardizes workers safety net, increases inequality,
unfair competition and economic imbalances.