The two social class descriptions that are present in Katherine Mansfield's short story "The Doll's House" are the upper class, which is represented by the Burnell sisters, and the very poor, lower class represented by the Kelvey girls.

With each social class comes a set of standards, rules, and expectations to be followed by its members. It is all, in part, due to social identity theory, which may help to explain the want and need of some individuals to be identified with specific power groups that distinguish them from other, less fortunate ones.

As such, the social class that the Burnells belong to is defined by specific behaviors towards each other, and then toward others of a different group. The expensive doll house, for example, is a very luxurious and expensive choice for a “thank you” gift. However, tokens of appreciation of that nature were the norm among the things that well-to-do people would do for one another.

As far as the treatment of others, the upper class kids of the school, and their parents, have a prescribed way of treating the Kelveys, and we can assume that this also applies to anyone of a much lower status.

....the line had to be drawn somewhere. It was drawn at the Kelveys. Many of the children, including the Burnells, were not allowed even to speak to them. They walked past the Kelveys with their heads in the air, and as they set the fashion in all matters of behaviour, the Kelveys were shunned by everybody. Even the teacher had a special voice for them, and a special smile for the other children.

Keep in mind that the school that the Kelveys and the Burnells attended was the only school in the area where both social circles resided. Hence, the poor and the rich were forced to coexist within this environment.

The sentence “the line had to be drawn somewhere” means that the separation of classes was an expected result of the upper class families having to mingle, against their will, with lower class students. Since the Kelveys were the weakest link, that is, the poorest of the poor in the school, and since they come from parents who had dubious reputations, the “obvious” reaction of the upper class people would be to completely shun the Kelveys and keep them away from their families and, especially, their children.

While the upper class lifestyle of the Burnells denotes opulence and fortune in the gift of the doll house, the type of poverty represented by the Kelveys is one of almost total destitution. If the Kelvey girls at least had a solid family unit staying together despite their financial woes, perhaps they would have gained one or two points toward redemption from social shunning. Instead, their mother was a washerwoman who dressed them up by making pieces of clothing out of the curtains and hand-me-downs of the people for whom she worked. Imagine the Kelvey girls knowing that the other girls see their thrown-away curtains and old clothes being worn by them. Even the narrator is at odds as to why the Kelveys' mother would do such a thing.

So they were the daughters of a washerwoman and a gaolbird. Very nice company for other people's children! And they looked it. Why Mrs. Kelvey made them so conspicuous was hard to understand.

Therefore, the type of poverty that the Kelveys represent is financial, social, and family-based. They lacked the basic support systems that would, at least, have made them feel secure and taken care of. Instead, the Kelveys were badly cared for and sent off to fend for themselves at school, entirely at the mercy of their much more fortunate peers.