From the summary:
Short- and long-term disability insurance programs replace some of the wages lost by people who cannot work because of a disabling injury or illness that is not work-related. Short-term disability insurance typically covers periods lasting less than 6 months, and long-term disability insurance lasts for the length of the disability or until retirement.
Those workers who are unable to work due to injury or illness and who do not have disability insurance coverage through their employers may seek benefits from Social Security Disability Insurance (SSDI). The number of SSDI claimants has grown over the past decade as younger workers and those in relatively low-skill, low-pay jobs have applied for benefits. This has prompted interest in the amount of coverage for workers in employer-provided disability insurance programs. This issue of Beyond the Numbers examines trends in employer-provided disability insurance coverage over time, explains the basic terms of coverage for typical plans, and estimates the costs to private employers.