Quarters of coverage (QC) is a term that was previously used to refer to work credits. Prior to 1978, employers in the United States would report employee earnings every three months (quarterly) instead of yearly. This was the system used by the U.S. Social Security Administration (SSA) to keep track of an individual’s eligibility for coverage under Social Security.
When a claimant applies for Social Security Disability Insurance (SSDI), the U.S. Social Security Administration (SSA) checks to see if the claimant has worked and earned enough to be covered by Social Security benefits. This is determined by the number of work credits the employee has. An individual receives work credit by earning money and paying taxes. Before 1978, U.S. employers reported the earnings of their employees on a quarterly basis; because of this, credits for Social Security were also earned on a quarterly basis and were called quarters of coverage (QC).