This post originally appeared at Janice Hardy's The Other Side of the Story.
Is worldbuilding for short stories different from worldbuilding for novels?
Yes and no.
You might guess that a short story would require less worldbuilding than a novel - but the size of the world itself is not the primary difference between the two. Short story readers will perceive world gaps, and be confused of frustrated by them, just as easily as novel readers. The biggest difference is that in a short story, you have very little room to explain or explore. Everything you do has to be done in as few words as possible.
Imagine that you're building a house. The first room of that house is the place where your reader enters the world. In a novel, that first room is full of doors. In a short story, it's all windows.
Doors can be opened. The novel format gives you the opportunity to send your reader through those doors, allowing you - and also requiring you - to explore a lot more of what lies in the rooms beyond. The most you get from an open window is the scent of fresh air. The short story format keeps readers confined, but if there's nothing to see outside, then they'll know something is wrong.
One of the wonderful characteristics of societies that I learned about while studying anthropology and linguistics is that large-scale trends in a society will tend to be visible even in small-scale interactions. I take advantage of this in my short story worldbuilding all the time. If you know a lot of large-scale things about your world, see if you can tighten your focus down and make them play out - i.e. be demonstrated, shown not told - on the smaller level. An entire system of phonology can be implied using a single unusual name. A system of social hierarchy can be implied by including small details of politeness in a single interaction between individuals. An economic model can be demonstrated by exploring the conclusions a character draws about the provenance of a single object.
Thus, in a short story, you should try to make every object and every interaction count. These things are not just working for your story but also for your world: they are the windows in your room. Realize that when you describe food, you're not only giving your character something to eat but potentially opening a view onto climate, agriculture, economy, socioeconomic conditions, and food culture. Realize that when you mention clothing, you're not just creating fashion but saying something about the value clothing has in your world. Realize that each person your character meets has a social role that illuminates the entire society - and that the opinion your character has of each person will give insight into that character's place within the system.
Of course, all this is true of novels as well. The demand for multi-tasking may be lower because you have more room with a higher word count, but it's always good to have your text do more than one thing at a time. Novels are expansive, so there are many opportunities to have the reader's sense of the world grow and expand.
The funny thing about short stories is that thought the amount of worldbuilding effort often seems disproportionately large, that effort will pay off. Readers can tell when the house has no windows - it's dark, and there's no air. If you choose the proper telling details to include, then you've placed your windows to maximize the view.
Give your readers something to see. They will thank you for it.