Millions of persons annually file claims for disability benefits from the Social Security Administration. If their claims are denied, the claimants can pursue appeal hearings before administrative law judges. The key issue before the administrative law judges is frequently whether there are a significant number of jobs in the national economy that the claimants can perform, despite their medical problems. To answer this question in an individual case, the administrative law judge often elicits testimony from a vocational expert who, inter alia, estimates the numbers of particular jobs that exist in the economy. If an ALJ determines that there are a significant number of jobs that the claimant can perform, the denial of the disability claim will be affirmed. The claimant can ultimately appeal the denial of the disability claim by the administrative law judge in the federal court system. Judge Richard A. Posner is a judge on the United States Court of Appeals for the Seventh Circuit which hears appeals from federal district courts in Illinois, Indiana and Wisconsin. In a series of appeals decisions involving Social Security disability claims from 2014 through 2016, Judge Posner criticized the reliability of the testimony of vocational experts when they estimate the numbers of particular jobs that exist in the economy. However, federal district court judges and magistrate judges in Illinois, Indiana and Wisconsin have generally interpreted Judge Posner’s critique to be non-precedential and have not relied on it to reverse the denial of disability claims before them. The purpose of this article is to describe Judge Posner’s critique of the testimony of vocational experts at Social Security disability hearings and to examine why this critique has had a limited effect on the decisions on disability claims in district courts in Illinois, Indiana and Wisconsin.