A common feature of most European social stratification and mobility research is the practice of allocating individuals to a social class based on their labour market position. One of the most influential contemporary social class schemas is the EGP (Erikson-Goldthorpe-Portocarero) schema. As we saw in Chapter 1, ESeC is essentially an update of EGP. One obvious disadvantage with the EGP schema is that there is no commonly agreed way of operationalizing it, since at the time of its construction quite different standards of occupational classifications were used across countries (cf. Erikson and Goldthorpe 1992). The most widely used algorithm for coding EGP was developed by Ganzeboom and Treiman, who use ISCO-88 (COM) as a starting point (Ganzeboom and Treiman 1996: 204-205). Hence, ESeC and EGP not only have the same theoretical base but also, at least so far as the EGP operationalization by Ganzeboom and Treiman is concerned, both are derived through a combination of the ISCO code and similar additional information. As a result, we are led to believe that the two schemas will be quite similar. Furthermore, if ESeC is viewed as an update of EGP we might expect it to be at least somewhat better in predicting class relevant outcomes. Consequently, the overall purpose of this chapter is to contribute to the validation of the ESeC class schema by comparing it with EGP. The analyses are based on the European Social Survey (ESS) Round 2.