What is Heading Hierarchy?
Heading hierarchy is the ranked structure of headings in a document: main section headings at the top level, subsections below them, and so on. Each level looks different, so readers can see at a glance how the parts relate, much like the levels of an outline.
Example of a Heading Hierarchy
- Level 1: Method
- Level 2: Participants
- Level 2: Materials
- Level 3: Questionnaire
- Level 2: Procedure
Why It Matters
- Readers can scan the structure and jump to the section they need.
- It shows the logic of the argument: a level 2 heading belongs to the level 1 above it.
- Screen readers let users move through a document by its headings, so a correct hierarchy is also an accessibility requirement.
- Word processors use it to build the table of contents automatically.
Formatting Guidelines
- Give each level a distinct, consistent format, and use the same format every time that level appears.
- Follow your style guide: APA defines five levels, each with its own alignment and bold or italic style; MLA and Chicago leave the format to you as long as it is consistent.
- Apply the word processor's Heading 1, Heading 2 and Heading 3 styles instead of formatting text by hand. In Word you can then promote or demote a heading in the Navigation pane.
Best Practices
- Never skip a level: a level 3 heading must sit under a level 2.
- Use at least two headings at any level you open; a section with one subsection usually needs none.
- Keep most papers to three levels; theses may need four or five.
- Make headings describe the content ("Sampling Procedure", not "Part B").
Full guide: APA Headings (7th Edition): 5 Levels + Example
Use case: Thesis writing assistant