Heading Structure

Heading structure is the hierarchy of titles and subtitles running down a page: one main heading naming what the page is, then subheadings marking each section beneath it. In the page's code these are real, labelled elements rather than merely larger text, which is how a machine can tell a section title from a sentence someone happened to put in bold.

Machines use that hierarchy the way a walker uses signposts. A system assembling an answer does not usually read your page from start to finish; it looks for the part that addresses the question in front of it. Clear headings let it find that part and lift it out. Absent or meaningless ones leave it skimming a wall of text and hoping.

The common failure is decorative headings. Five sections titled some variation of Welcome, or Our Approach, or About — a corridor with no doors. Set Our Services beside What we charge to repair a boiler in Zürich. The second is a heading a machine can navigate to, and it is also, not coincidentally, the one the human being was looking for.

There is a related fault worth naming: headings that are only large text. If a line was made big and bold without being marked as a heading, the page looks structured to you and arrives as one undifferentiated block to everything else. This is usually a five-minute correction in whatever built your site, and it is invisible until somebody checks.

The human translation is that a heading is a promise about what follows. Write the promise you would make out loud to someone standing in front of you, and the machine benefits almost by accident.