Policy makers and researchers need wider access to confidential microdata--data about individual people, households, businesses, and other organizations--in order to make informed decisions about public policy. Confidentiality protection, however, is one of the critical aspects underlying research on human subjects and must be respected. The challenge is to protect data confidentiality while at the same time allowing wider data access to researchers and analysts. Several recommendations are made that should result in wider access to both anonymized public-use data and to potentially identifiable microdata. Recommendations include the advice to use a variety of modes of access to data of different levels of detail and precision; develop techniques to provide public-use datasets that maximize information quality without increasing disclosure risk; restrict access to public-use data to those who agree to abide by the confidentiality protections governing the data; and to use licensing agreements for statistical and other agencies that seek access to confidential data. Other recommendations focus on educational and professional organizations and direct them to train researchers in ethical issues related to data collection, analysis, and distribution and to develop strong ethical conduct codes governing the confidentiality of personal data. Following the introduction in chapter 1 on the importance of expanding access to research data, chapter 2 overviews the significant changes that have occurred in the past decade related to researchers’ access to government microdata. Chapter 3 explores the benefits of wider access to microdata, including the role of data in the scientific process and the contribution that microdata makes to public policy. Chapter 4 focuses on the causes and consequences of confidentiality breaches while chapter 5 reconciles the benefits and risks of expanded access to microdata. Footnotes, references, appendixes