What Happens When a PDF Reader Hits a Two-Column Resume

How a reader turns two columns into one

A PDF does not store columns, paragraphs or lines. It stores positioned text fragments, each with an x and y coordinate. A reader reconstructs lines by grouping fragments whose vertical positions fall within a small tolerance, typically a few points.

When a resume has two columns, fragments on the same horizontal band share a vertical position. The reader collects one fragment from the sidebar and one from the body, emits them as a single line, and moves on. The result is a line that was never written: a phone number welded to a job achievement, or a section heading fused with a bullet from an unrelated section.

This is not a bug in the reader. It is the only reasonable thing a coordinate-based grouping algorithm can do when unrelated content shares a vertical position. The layout itself is the cause.

What the extracted text actually looks like

Theory only goes so far. Here is the verbatim output from one of the two-column resumes in the study, unedited. Every highlighted line was assembled by the reader from two unrelated parts of the page.

The name and the section heading fused into one line. The email address and a date range fused into another. A phone number landed in the middle of a bullet about Kubernetes. The words are nearly all present, 97.9% of them, but the sentences they form were never written by anyone.

This is the core finding. Word recovery is not a useful measure of quality when the words are rearranged into nonsense. A keyword search for "Kubernetes" might still match, but anything reading the text as prose, whether a human reviewer or an LLM summariser, sees gibberish.

The numbers across all profiles

Across all 9 resumes, the two-column layout recovered 97.9% of intended words. Reading-order fidelity, measured as the longest common subsequence against the intended sequence, dropped to 83.6%. And 30.5% of output lines were welded from unrelated content.

Compare that to the single-column control: 100% recovery, 100% order, 0% welding. The gap in recovery is small. The gap in order and welding is where the layout separates from the control.

Block integrity, which measures whether labelled sections like Experience and Skills stayed internally coherent, remained at 100% even in the two-column layout. The sections were still there. They were just interleaved with content from the other column.

Narrowing the gutter makes it worse

We tested a second two-column variant with a narrower gutter. Recovery stayed at 97.9%, but welding rose from 30.5% to 33.1% and order dropped from 83.6% to 83%.

The reason is straightforward. The reader decides whether two fragments belong to the same line partly by measuring horizontal distance. A wider gutter gives the algorithm more space to recognise a column boundary. A narrow gutter removes that signal, so more fragment pairs on the same band are merged.

If you insist on a two-column design, wider gutters are measurably better. They do not eliminate the problem, but they reduce the rate at which unrelated content fuses.

Why keyword matching can pass while comprehension fails

At 97.9% word recovery, most individual keywords are still present in the extracted text. A simple search for "Kubernetes" or "PostgreSQL" will find them. This is why two-column resumes do not always fail outright; some systems do not read for meaning, they scan for terms.

But any process that reads the text as connected prose, whether that is a human reviewer skimming the extracted version, an LLM summarising the candidate, or a parser trying to attribute a bullet to a specific role, will encounter lines that make no sense. The phone number is in the middle of a sentence about services migration. The skills heading is welded to an achievement from a different section.

This distinction matters for practical advice. If the only thing between your resume and a human is a keyword filter, a two-column layout may survive. If the text is ever read as prose, and increasingly it is, the layout creates exactly the kind of noise that degrades comprehension.

What to do about it

The cleanest fix is the simplest one: put the body of your resume in a single column. The control scored 100% recovery, 100% order, and 0% welding. No ambiguity, no interleaving, no welded lines.

If you want to keep a two-column design, the data suggests two specific things. First, widen the gutter. The difference between the standard and narrow gutter variants was 33.1% versus 30.5% welding, which is measurable and in the right direction. Second, keep the sidebar short and self-contained. The worst welds happen when sidebar content sits beside body content that must stay together, like a bullet point or a job title.

A narrow rail with only your name, contact details and a short skills list, separated from the body by generous whitespace, is a smaller risk than a full-height sidebar carrying section headings alongside experience bullets. The less content shares a vertical band with unrelated content, the less there is to fuse.

• Single column for the body is the safest choice.
• If keeping two columns, widen the gutter as much as the design allows.
• Keep nothing in the sidebar that must stay attached to adjacent body content.
• Test the result: paste the extracted text and check whether lines read as written.

What this test does and does not show

The corpus is synthetic: all 108 files were generated with pdf-lib rather than collected from real applicants. This means every variable is controlled and the intended text is known exactly, but it also means no one's personal data is involved.

One reader was tested: PDF.js, the same library the X-ray runs. Employer systems use different extractors and may produce different results. Findings describe how these formatting choices behave under extraction, not how any particular company screens.

The study tested 9 profiles across a range of fields. All used the same two-column geometry. Different column widths, different sidebar content, or different extraction libraries could shift the numbers. The direction of the finding, that side-by-side layout causes interleaving, is a property of how coordinate-based text grouping works, not of any particular file.