How ATS Systems Work and Why Your Resume Gets Rejected

Published by Aragorn · ZorbTool Blog

You spent hours perfecting your resume. You are genuinely qualified for the role. You submitted your application and heard nothing. If this sounds familiar, there is a good chance your resume was never seen by a human — it was rejected by an Applicant Tracking System before it ever reached a recruiter's desk.

What is an Applicant Tracking System?

An Applicant Tracking System, or ATS, is software used by employers to manage the recruitment process. Large companies receive hundreds or even thousands of applications for every open position. It is simply not possible for human recruiters to read every resume. ATS software automatically screens, sorts and ranks applications based on a set of criteria defined by the employer, allowing recruiters to focus only on the top-ranked candidates.

According to research by Jobscan, over 98% of Fortune 500 companies use ATS software. Even many smaller companies now use ATS tools like Greenhouse, Lever, Workday and Taleo. If you are applying to any established company, the chances are very high that your resume will be processed by an ATS before a human ever sees it.

How ATS Software Screens Resumes

The primary screening method used by most ATS systems is keyword matching. The software extracts keywords from the job description — skills, qualifications, job titles, tools, and other relevant terms — and then scans your resume for those same keywords. Resumes that contain more matching keywords receive higher scores and are more likely to be passed to human reviewers.

Most ATS systems are surprisingly literal in their matching. If the job description says "project management" and your resume says "managing projects", many systems will not recognise this as a match even though the meaning is identical. This is why tailoring your resume to each specific job description is so important.

Common Reasons Resumes Fail ATS Screening

Missing keywords is the most common reason resumes are filtered out. If the job description mentions specific skills, tools, or qualifications and your resume does not include those exact terms, your score will be lower. Using unusual formatting is another frequent problem. ATS software parses resume text and can struggle with tables, text boxes, headers and footers, and complex formatting. Information in these elements may not be read correctly.

Submitting in the wrong file format can also cause problems. Most ATS systems handle standard Word documents (.docx) and PDFs well, but some older systems struggle with certain PDF types. Using generic resumes without tailoring them to each job description almost guarantees a low ATS score. A resume that is perfect for one role may be almost irrelevant for another even within the same industry.

How to Optimise Your Resume for ATS

Start by carefully reading the job description and identifying the key skills, qualifications, and requirements. These are the keywords you need to include in your resume. Incorporate missing keywords naturally into your experience descriptions — do not simply list keywords at the bottom of your resume as this can look like keyword stuffing to both ATS systems and human reviewers.

Use both the full form and abbreviation of important terms where appropriate. For example, include both "Search Engine Optimisation" and "SEO", or both "Artificial Intelligence" and "AI". Use standard section headings like "Work Experience", "Education" and "Skills" rather than creative alternatives. Keep formatting clean and simple — avoid tables, text boxes and decorative elements that ATS software may not parse correctly.

Check Your ATS Score Before Applying

Before submitting any application, it is worth checking how well your resume matches the job description. ZorbTool's free ATS Score Checker analyses your resume against any job description, identifies missing keywords, and suggests specific sentences to add. Everything runs in your browser — your resume is never uploaded to any server.