[Excerpt] Social mobility studies begin with the assumption that movement from any blue-collar job to any white-collar job represents unmitigated betterment of an individual's or generation's social status. These studies represent this movement across the collar line in a linear fashion, following the movement from fathers' occupations to sons'. This is the basic method that Jiirgen Kocka suggested historians could use to illuminate "the relevant lines of distinction, tension and conflict segmenting and dividing the emerging working class internally" and the "outer boundary" of that working class, the visibility and rigidity of "the distinction between workers and those who own and control." However, the linearity of traditional social mobility studies conceals diversity among siblings within a single family and ignores altogether the significance of women's changing roles in the paid labor force.