This document discusses how changes in demographics and labor markets affect eligibility criteria for Social Security Disability Insurance (SSDI). It notes that SSDI outlays and participation have doubled in recent decades. While the aging workforce partly explains this, disability rates have remained flat. The document also discusses how a growing share of SSDI awards are decided based on vocational factors like age, education, and experience rather than medical conditions alone. However, it argues these vocational criteria are outdated and no longer reflect today's labor market which has shifted away from manual work to more sedentary, service jobs. The document recommends eliminating or modifying vocational criteria in SSDI eligibility determinations to better align with modern labor market realities.