Logical Reading Order

The sequence in which content within a document is presented to assistive technologies, which should match the intended logical flow of the content as a human reader would understand it. In PDFs, the logical reading order is determined by the tag tree structure, not the visual layout — this is critical because PDF content can be visually arranged in multi-column layouts, sidebars, or complex page designs that differ from the underlying content stream. Correct logical reading order ensures that headings precede their sections, multi-column text reads in the proper sequence (not across columns), inline elements like footnotes and references appear in context, and figures with captions are positioned appropriately in the flow. Incorrect reading order is one of the most common and disorienting PDF accessibility failures for screen reader users.