An ideal cancer care data system would allow hospitals and health plans to assess their care relative to national or regional norms and to identify ways that care could be improved. Facilities and plans would receive periodic, easy-to-read charts comparing their recent experience against national or regional norms. For health plans, performance scores could be published by national accrediting bodies such as the National Committee for Quality Assurance (NCQA). Hospitals could have scores considered by groups such as the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). Publicly available information on quality could potentially inform decisions about care made by consumers and healthcare purchasers.

Even though consistency in measurement is often desirable so that trends can be accurately monitored, cancer care data systems need to be flexible so that accommodations can be made for new evidence on quality measures, changes in healthcare delivery, and technological innovation.

Maintenance of sensitive personal health information, such as the diagnosis of cancer, in large computerized databases raises serious issues regarding privacy and confidentiality. Legal protections must be in place to ensure that data collection is appropriate, that information is stored securely, and that access to the information is controlled. Federal and state laws and regulations governing privacy, confidentiality, and data security must be strictly enforced while at the same time allowing important registry functions to proceed. Data linkages using personal identifiers such as social security number or birth date, for example, are necessary to eliminate duplicate reports of a case from different healthcare providers. A relatively new application of linkage is the assessment of quality of cancer care.