Created by the Healthcare Quality Improvement Act of 1986, the National Practitioner Data Bank (NPDB) is intended to provide a national clearinghouse of doctor discipline and malpractice payment information to doctors, insurers, health care providers and other interested parties. The NPDB is administered by the Health Resources and Services Administration (HRSA), an agency within the Department of Health and Human Services. For many years, journalists and public records researchers (vetting potential malpractice legal actions) have matched information from the NPDB Public Use Data File against public malpractice settlement information to piece together the fullest available medical provider disciplinary and sanction information. As an example, journalists and researchers reviewing a specific physician's practice history might encounter a malpractice settlement in a court case that lists the exact amount of the payout. They would then take this settlement amount and query it in the NPBD Public Use Data File. Once a match was obtained, the researcher or journalist could pull the unique physician identifier from the NPBD Public Use Data File and sort around that number to reveal any additional sanctions or malpractice payments.
This "backing-in" technique can be employed when at least one consistent data point is available within an anonymized data set (i.e., one where only a unique identifier and not a name is used as in the case of the NPBD Public Use Data File.) Once matches are obtained by backing-in, other verifiable points of information (i.e., state of practice, location of practice, nature of disciplinary action by code) can be canvassed to determine if the match is appropriate.
Up until this month, there were no restrictions on using NPDB data to "back-in." Recently, however, the HRSA created terms of use designed to restrict NPBD data to researchers looking for macro trends and to specifically prohibit matching NPDB data with outside public records to develop practitioner identity. Expect the new terms of use to be the first, not last word on the subject of whether this data should be available without restrictions.
For some real world examples of how NPDB data has been used by journalists follow this link from the Association of Health Care Journalists which is also linked through this story in The New York Times on the on-going NPDB data access kerfuffle.
Much more information on the NPDB data, including annotations on coded fields, is available here in the NPDB Guidebook.