Article at a glance:

What's holding back online medical data

• Champions of a US national online medical-data system argue that it would help improve the quality of care while cutting costs for patients, employers, and insurers alike.
• Skeptics say that the start-up costs are high—possibly more than $150 billion—and that the technical and policy challenges are daunting.
• But champions and skeptics alike are missing a more important point about such a system—that its costs and benefits would fall unevenly across key groups of participants.
• Until the misalignment of costs and benefits for stakeholders in a national system is addressed, other debates are secondary.