An employee has the right to end his or her relationship with the employer at any time. This employee’s right indicates that an employer-employee relationship exists.

An independent contractor usually agrees to complete a specific job and is responsible to complete the job at a satisfactory level or he or she will be liable for breach of contract. However, independent contractors may enter into short-term contracts or negotiate limits on when they are liable for nonperformance. Some professionals, such as doctors or attorneys, are able to terminate their contractual relationship without penalty.

Social Security Handbook, section 823 : Do you have the right to end your relationship with your employer at any time?