What makes a collection of people a 'class'? Does grouping people into classes help to explain anything?

Essay from the year 2003 in the subject Sociology - Social System, Social Structure, Class, Social Stratification, grade: 2.1 (B), Oxford University (New College), 4 entries in the bibliography, language: English, abstract: Class is a concept much used in both sociology as well as everyday language, but it is surrounded by much confusion about its meaning. There are many different definitions of class and many different views on how people can be grouped into classes. In sociology there is an ongoing debate whether or not class is a relevant concept in contemporary societies and whether it can be used to explain any issues. I am going to look at the different meanings of 'class'. Further I am going to investigate whether grouping people into classes helps to explain anything. The use of class to indicate lifestyle, prestige or rank is probably the most commonly used sense of the term. Here class is bound up with hierarchy, of being higher than or lower than some other person or group. Rank is often indicated by lifestyles and particular patterns of consumption. Marx and Weber have provided two of the most influential explanations about what classes are and how they influence society. Marx believed that systems of stratification derive from the relationships of social groups to the means of production. He used the concept class as referring to the main strata in all stratification systems. A class is a social group whose members share the same relationship to the means of production with the ruling class oppressing the subject class. He argued that on the one hand there exists a 'class in itself' which is just the relationship of the social group to the means of production, but on the other hand a social group only fully becomes a class when it becomes a 'class for itself', when its members have class consciousness and class solidarity.