Why are skill bars a problem on an ATS resume?

Skill bars show your level as a picture, and applicant tracking systems generally read text, not pictures. The skill name may be read, but the level usually is not, and in some designs the whole bar, label included, is part of a graphic that cannot be read at all.

Skill bars also cause problems for people:

• They have no shared scale. Is a bar four-fifths full "advanced" or "good"?
• They invite awkward questions, such as why your communication bar is not full.
• They take a lot of space for very little information.

What to use instead:

• A plain list: "Excel (advanced), SQL (intermediate), Python (basic)".
• Evidence in your bullets: "Built monthly sales reports in Excel using pivot tables and Power Query."
• A recognised scale where one exists, such as CEFR levels for languages (B2, C1).

If you love a visual design, keep it for a portfolio website. On the resume file you upload, plain text gives software and recruiters the information they actually need.