Health data constitute a significant resource in most OECD countries that could be used to improve health system performance. Well-intended policies to allay concerns about breaches of confidentiality and to reduce potential misuse of personal health information may be limiting data use. A survey of 20 OECD countries explored the extent to which countries have developed and use personal health data and the reasons why data use may be problematic in some. Countries are divided, with one-half engaged regularly in national data linkage studies to monitor health care quality. Country variation is linked to risk management in granting an exemption to patient consent requirements; in sharing identifiable data among government authorities; and in project approvals and granting access to data. The resources required to comply with data protection requirements is a secondary problem. The sharing of person-level data across borders for international comparisons is rarely reported and there were few examples of studies of health system performance. Laws and policies enabling data sharing and data linkage are needed to strengthen national information infrastructure. To develop international studies comparing health care quality and health system performance, actions are needed to address heterogeneity in data protection practices. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.