Often, in order to answer our main research question, we need to answer a series of smaller sub-questions.

Take a look at this image of a tree. It’s a drawing by Bruno Munari, an Italian writer and artist. According to Munari (2013), we can observe two patterns of growth for a tree with two branches:

1. The branch that follows is always slenderer than the one before.
2. Starting with the trunk dividing into two limbs, each limb will subsequently divide into two

Think of research questions and research sub-questions like this tree. Your main question is the trunk. Your research sub-questions are narrower, more specific questions that branch off the trunk, your main question, but are still connected to the trunk. Like the branches in this tree, your research sub-questions can even yield sub-questions of their own.

References

Munari, B. (2013). Drawing a Tree. Mantua, Italy: Edizioni Corraini.