HR brings you in to do a first round employment screening. It helps to have someone pass your resume on to a recruiter due to the shear volume of applications they receive. Thousands apply and never hear anything back. Make the recruiter's life easy and get in touch with them. 20,000+ employees its understandable you should get a referral before you submit an application. After you meet with HR for a brief interview and paperwork to get you in the system, the next round will be with the Hiring Manager of the department you are applying for.