We Don't Know What We Don't Know

Many thanks to Dr. Kevin Horton of ATSDR for his assistance with my questions in my post from July 26, "Who are the 15 Percent?"

The bottom line is that "the 15%" in the recent Registry report does not represent those people with ALS who are not located via the administrative databases.  It only speaks to the quality of what is found within those Medicare, Medicaid, VA files.

The recent Registry report does not address the completeness of the ALS Registry in finding all cases of ALS in the United States.

So how did I (and some others) get a completeness expectation?  I felt foolish yesterday that I completely missed the boat by thinking that the Registry was designed to find around 85% of people with ALS via the passive mining of administrative databases.

But, yes, there had been assertions early on in the Registry approval process that the administrative files would contain all but 15-20 percent of cases of ALS in the Unites States.  Yes, per Dr. Horton, some original pilot sites indicated that they could find more than 80 percent of PALS via administrative files. We weren't hallucinating.

Take a look --
http://web.alsa.org/site/PageServer?pagename=ALS_Registry_Background

... the CDC has created an algorithm that will enable the Agency to accurately identify approximately 80-85% of ALS cases in the United States by examining large national administrative databases ...

...In order to identify the remaining 15-20% of cases, the CDC has launched an on-line web portal that allows people with ALS to self-enroll in the Registry via a secure website...

Now I understand that today, the data in the Registry report did not swing at this completeness nail at all (that I certainly had my eye on).   They did not address how many people with ALS would potentially be outside of the administrative data sets.  Per Dr. Horton, they will do future analysis on this.

Stephen Finger has a graphic in his op-ed that speaks volumes --
http://www.huffingtonpost.com/stephen-finger/national-als-registry_b_5620631.html

His point is important, especially since the Registry report is making headlines without any important context of completeness.

We have a Registry of people with ALS who are in "the system."  They were either in administrative databases or heard and responded to the call to self-enroll.

We have no idea of how many other people with ALS are living in the United States today.

We simply don't know what we don't know... and that's important to understand.