"The Garden Party" and "The Doll's House" both deal with issues of class. They differ, however, in that in "The Garden Party," class is examined from the point of view of the impact it has on an upper class character, Laura, whereas in "The Doll's House," the focus is its impact on two lower class girls, Lil and Else Kelvey.
In "The Garden Party," Laura enters the home of a lower-class person who has been killed and is shaken by the experience; in "The Doll's House" the Kelvey girls enter an upper class domain when they are allowed inside the yard of the Burnell's house to see the marvelous dollhouse. Laura ends up crying and saddened at the inchoate emotions the visit to the poor cottage brings up for her, but the Kelvey girls experience joy and satisfaction at having had the chance to glimpse the glamorous doll's house.
The stories differ in that at the end, we get, at least from the exterior, an inkling of what the Kelvey girls are thinking and feeling: in the "The Garden Party," the feelings of the lower class residents are opaque—they are kept distant from us. Mansfield's modernism shows in both stories in the lack of an omniscient narrator to sort things out for us and explain what is going on. We experience "The Doll's House" through the shifting perspectives of characters in the story and the subjective narrators. The person in "The Doll's House" who keeps referring to "our Else" is particularly elusive: who this narrator is and why she considers Else "ours" is never explained. Is it a Kelvey family member or is it the perspective of a later employer? In "The Garden Party," Mansfield sticks to Laura's point of view, which is very much subjective.
The story's are both modernist, too, in that outward plot resolution is less important than what is happening inside the minds of the characters.