This report provides a historical examination of the SBA's size standards, and assesses competing views concerning how to define a small business. It also discusses H.R. 585, the Small Business Size Standard Flexibility Act of 2011, and H.R. 4, the Jobs for America Act of 2014], which would authorize the SBA's Office of Chief Counsel for Advocacy to approve or disapprove a size standard requested by a federal agency for purposes other than the Small Business Act or the Small Business Investment Act of 1958. The SBA's Administrator currently has that authority. It also discusses P.L. 112-239, the National Defense Authorization Act for Fiscal Year 2013, which requires the SBA to make available a justification when establishing or approving a size standard that the size standard is appropriate for each individual industry classification. It addresses the SBA's recent practice of combining size standards within industrial groups as a means to reduce the complexity of its size standards and to provide greater consistency for industrial classifications that have similar economic characteristics.