The change in class structure is the structural changes between classes in primary, secondary, tertiary, quaternary, and quinary sectors. The changes are generally unidirectional from primary to secondary and secondary to tertiary. In countries like India, there is a switch directly from primary to tertiary by skipping the secondary industrial sector. The behavioral patterns, social roles, technologies, and cultures are different in the social classes created in each sector.
Due to various changes like employment since the late 19th century, there have been significant changes in the class structure of modern economies. As technology has enabled fewer people to perform more, agriculture and other primary production sectors like mining, forestry, and fishing have declined.
Many people migrated into industries after abandoning the countryside. Compared to the manual working class, the white-collar middle class started to expand in the 1950s, and by the turn of the 20th century, it had surpassed blue-collar jobs.
How we define, quantify, and categorize class may determine precisely how the class structure of sophisticated civilizations has evolved. Compared to John H. Goldthorpe and his European colleagues, Erik Olin Wright, a US Marxist, developed a much bigger working class. Nevertheless, the broad patterns of evolution hold whether either model is applied to historical and modern data.
The change in the class structure influences other outside classes due to urbanization, industrialization, and globalization. The joint family system in India is changing to nuclear families and single-parent families due to extensive influence from Western countries.