Wednesday, December 15, 2010


Mae West once said that "between two evils, I always pick the one I never tried before."

Scott Schumacher and I shared a panel at an ONC Privacy and Security Tiger Team hearing on patient matching (December 9th hearing).  There's some excellent testimony - well worth reading through.

We had a great exchange on the relative merits of linking versus merging which Scott summed up in a recent post: Why merging is evil.  "The criticism of the linked approach mostly concerns computation inefficiency. That is, if a user queries a particular member multiple times, the often-complex composite-view rules need to be executed each time. In the merge model, these rules are only executed once. In the merge model, we sometimes lose data and almost always lose the initial structure of the data. That is, we have lost information. In today’s world, information is precious. Losing it is evil."

One Tiger Team member commented that "There are possibly more evil things that can be done than a merge."  There are situations where data loss or loss of structure may introduce risks to safety or privacy.  But  I will set aside the use of "evil" in this regard as hyperbole.  

Scott's point is right as it relates to the linking systems for health information exchange (nation-wide exchange, this is the one, to channel Mae, that we've never tried before).  But it's far less obvious in connection with the linking systems inside of a care delivery organization.  In a health information exchange world, keeping records separate is good architecture and good practice.  The provider has no way of knowing and verifying the records of another provider.  The farther you move away from the source provider and the patient/person, the more important it is to maintain the source data intact.  Keeping records separate and linked for "Rich Elmore", "R Elmore", "Richard Elmore", and "Richard Ellmore" among distinct providers is critical to ensuring that the best possible rigor is applied at any point in time when the data is to be presented for analysis and use.

The Tiger Team members in their post-hearing discussion (MP3 audio on 12/10 from 1:02 - 1:06) made the argument that care providers will generally want to manually correct errors, not persist them, and would do so manually if  merge capabilities were not available.  They also pointed out that merging does not necessarily result in loss of the data structure - there are merging approaches such as creating a composite from the duplicate patient records that avoids this issue.

Ultimately, the Tiger Team concluded that this question (regarding the impact on the clinical records  downstream  from the patient linking system) is out of scope.  In other words, it's not a question of  "what you do downstream when you discover a possible link.  If you built a linking system that... lost all evidence that (two patients) were separate at one time, then that would be evil.  However, what you do within your medical records system with separate linkages or merged data - that's a separate issue."  

Some important related but unresolved questions were also posed by the Tiger Team members.  What is the physician's role in correcting the record when care has been provided based on an improperly merged (or linked for that matter) medical record?   And what are the responsibilities of these "downstream" systems related to handling errors in linking or  merging?

Patient matching and the downstream system implications are ever more important as health information exchange takes center stage.  Scott deserves credit for grabbing our attention with his "evil commentary".


Brian Ahier said...

Great post Rich ~ appreciate your insights...

Globalhospitals said...

"between two evils, I always pick the one I never tried before."
well said