The National Academy of Sciences report, Monitoring International Labor Standards : Techniques and Sources of Information, shows that assessing compliance can be done thoroughly and transparently, allowing government officials, multilateral agencies, "socially responsible" investors, and nongovernmental organizations to identify where they differ on crucial aspects of the assessment process.Although the report, prepared by a committee I chaired, carefully avoids any discussion of inserting labor standards into trade agreements, the analysis has important implications, in my opinion, for the trade and labor standards debate. It reveals how far the world is from agreement on determining compliance so as to instruct trade dispute panels and appellate bodies ; it shows that the proposal to "let the ILO [International Labor Organization] determine innocence or guilt" could not possibly work except for simple cases in small, passive states ; and it shows that formulating a multilateral jurisprudence for use in trade and labor cases would require fundamental, substantive changes to labor law in both developing and developed countries, including the United States. This policy brief outlines the challenges in assessing compliance with the four ILO core labor standards, lays out a simple framework for "due diligence" in investigating compliance-which could apply to China, Mexico, Sweden, or the United States-and addresses the implications for trying to include labor standards in modern trade agreements.