In modern society, social stratification determines position of individuals in relation to other classes, occupations, gender and races. Most theories of post-industrialism argue that the stratification systems of industrial society are broken down by the new flexibility of occupational systems. Social stratification determines relations between family background, educational paths and opportunities, and types of occupational definition and identity are fundamental to the analysis of social class in modern societies.
Researchers (Brym and Lie) note that theoretical traditions relate to particular social structures. Social stratification takes its roots in class division and class struggle described by Karl Marx. For example, the low position accorded to all manual labor in the prestige ranking approach of US sociologists can be seen as a reflection of the position of skilled manual work in that society, where, with the exception of very few traditional craft occupations, manual skills are not externally certificated occupations, conveying some autonomous social status and in the organization of which trade unions might have some role, but the property of employers (Bian 91). Critics (Brym and Lie) decompose their model of this stability into four components which will account for patterns of mobility between classes: hierarchy, inheritance, sector, and affinity. Hierarchy refers the different authority levels which distinguish some occupations from each other. Inheritance refers to the tendency of families to transmit class positions across generations. Sector refers primarily to the difference between rural and industrial social experience, and affinity to the social links that relate some classes closer together. Class is seen as an attribute of individuals but derived from their total household circumstances. This is determined by the character of their study, which is to examine the mobility trajectories of individuals (Shihadeh and Steffensmeier 730). Such an approach is less easily able to consider classes themselves as collectivities with certain shared attributes and behaviors, unless it can be assumed that the individuals who comprise a class have overall household characteristics which derive primarily from the characteristics of the class. This assumption is fulfilled in the case of people who are the predominant earners in their households, of which they are the 'heads'. In such cases the income and other conditions associated with the occupations that comprise the class will be similar across all households of class members. The classic mid-century compromise society of a male breadwinning workforce would be an example of such a society. Where most working women are concerned the assumption is not satisfied: the occupational classes they form are often comprised of people coming from diverse household backgrounds, and the earnings of these households are usually not predominately derived from the women's own labor-market position. Indeed, to the extent that women contribute to household income, the central assumption ceases to be true for men as well as women. This development has important implications for classes as social collectivities (Bian 91).
From the sociological point of view, the concept of social stratification is closely connected with social mobility. Fundamental is a distinction between absolute and relative social mobility. In their research, Bian discusses social stratification in Chinese society in cultural context. Shihadeh and Steffensmeier research social strification in terms of ocial control and crimes among black population. The former concerns shifts that take place through changes in the size of occupational groups and in the family sizes of people in these groups in the parent generation. The latter concerns any changes that take place in mobility chances once the former have been taken into account. For example, let us imagine a society with no immigration from abroad and with just two relevant occupational groups: managers and workers (Bian 91). If over time the demand for managers grows relative to that for workers but existing managerial families do not produce enough children to fill the new managerial posts in the next generation, then some workers' children must experience mobility into the managerial class even if nothing happens to improve equality of opportunity and managerial children continue to have privileged opportunities to succeed their parents. The concept of social stratification is important because it helps sociologists and economists to explain and determine social relations and interaction between individuals from different social groups and strata. The mobility that then takes place will of course be highly significant to the individuals concerned and may involve certain interesting social changes through the arrival of 'newcomers' to the managerial class. It would be wrong to interpret such a change as marking any increase in the openness of the society or in its equality of opportunities. This latter occurs only if relative mobility takes place that is if people from workers' families are moving into the managerial class in greater numbers than required by changes in the size of the families of the two groups in the parental generation and of the occupational groups in the second generation (Shihadeh and Steffensmeier 732).
It is likely to be a class that fails to meet many of the criteria required for a class to be a demographic entity with widely shared characteristics among its members. his seems to result from considerable diversity in the formal rules which relate educational qualifications to occupational placement (Bian 91). Where rules are left much looser they might have more chance. In the general systems families have little choice other than to place all their emphasis on their children maximizing opportunities of any kind; and the education system has no particular need to adapt itself to signals coming from the occupational system about types of qualifications. On the other hand, as we have noted, there is a much clearer hierarchy running down from managerial positions, with manual work of all kinds being lowly ranked (Shihadeh and Steffensmeier 734).
As social stratification and social change is not a stable process, social theories need constant revising and revision. This is explained by the fact that the most important factor determining social stratification chances is sector (that is, the boundary between the agricultural and all other sectors), while the most important set of factors is a cluster of different aspects of inter-generational inheritance. Hierarchy and affinity were considerably less important, though they did have some effect. This Stratification in advanced societies cannot be seen in terms of an ordered prestige hierarchy. Two fundamental features of class relations-relative similarities and differences between classes and varying degrees of hierarchy among them-accounted for the main structures of relative mobility chances, testifying to the continuing validity of occupationally based classes as structural features of modern societies (Bian 91). And in each case the strength of inheritance demonstrates the continuing role of families in sustaining class patterns across generations. Researchers are primarily concerned with the development of advanced industrial society, and cannot tell us much about the hypothesized shift to post-industrialism, which in most countries developed strongly only after the years in which their data were gathered (Shihadeh and Steffensmeier 735).
In sum, theory of social stratification shows that the main sectoral transition with which individuals are concerned is social changes and position of a person on a social ladder. Social stratification is analyzed through transition between manufacturing and the various services sectors; male manual workers in manufacturing industry stand at the centre of much of their analysis, and there is very little on the emerging new class of routine nonmanual women in various services. In a context of frequent change and of a general upgrading of skill levels, researchers predict a further decline in the power of family to influence educational outcomes. Many of the predictions of declining class inequality have been oversimplifications; the clarity of class identities may be declining, but levels of inequality associated with them might be increasing.