Why ATS checkers give different resume scores

An ATS is not one standardized exam

Employers configure different recruiting systems, application questions, workflows, and screening practices. Some systems parse a document into fields such as contact details and work history. A resume checker then adds another layer: its own rules for structure, content, and job relevance.

That means two checkers can inspect the same PDF and return different numbers without either number reproducing the employer's decision process. The score is a model of readiness, not a credential issued by a shared ATS authority.

Four reasons the number changes

A useful comparison starts by separating parsing from scoring. Parsing asks what text and sections the system can read. Scoring asks how much value the checker assigns to what it found.

• Extraction: one parser may preserve columns and headings while another reads them out of order.
• Inputs: a generic resume audit and a resume-versus-job-description comparison answer different questions.
• Rules: checkers use different lists for headings, action verbs, keyword aliases, bullet length, and measurable outcomes.
• Weights: one tool may prioritize job keywords while another gives more credit to formatting or writing style.

What official vendor documentation does show

Official product documentation supports a narrower conclusion: file readability and document structure can affect parsing. Lever says its parser accepts Word, PDF, RTF and other text formats, cannot parse image files, and suggests checking whether the text can be highlighted. Greenhouse lists PDF and DOCX among supported uploads and separately warns that image-based files, complex tables, headers, footers, and columned layouts can contribute to unsuccessful parsing.

Those facts justify testing extractable text and clear structure. They do not justify claiming that one public score predicts how every employer will rank a candidate.

How to compare two ATS reports

First, look for agreement on observable facts: Was the email detected? Did the experience section parse? Is the PDF text selectable? Are important job requirements genuinely absent? Fixing those issues has a clear reason.

Next, inspect advice that depends on preference or a proprietary threshold. A checker might prefer a specific bullet count or keyword percentage. Treat that as a prompt to review the section, not a command to force the document toward a magic number.

How Ryzio makes its score inspectable

Ryzio uses deterministic checks: the same extracted resume and job-description input produce the same audit. The result exposes category scores, individual findings, earned points, and suggested fixes. AI does not assign the ATS score.

The method still has limitations. Ryzio is not connected to an employer's configured ATS, and some layout signals are inferred. The public methodology names those limits so the score can be used as guidance rather than a guarantee.