A careful examination and evaluation of definitions across nations shows that, the "small scale industries" (SSIs) or "micro, small, and medium-sized enterprises" (MSMEs) have different meanings and implications. Hence this definition evolved over time. The informal sector is distinguished by diverse employment, organization of production, and ties to the formal sector. The SSIs/MSMEs lack a formal and hierarchical structure.
Accordingly, changes in industrial structure and their consequences for small businesses and employment must be considered in a multidisciplinary context. The role of MSMEs in extricating developing nations from the 'low-level equilibrium trap' and breaking ‘the vicious circle of poverty’ is in conformity with economic theory and historical experience of numerous countries. Since standard quantitative yardsticks have yet to be definitively defined, the main features of MSMEs might be investigated in terms of qualitative criteria.