Monday, April 2, 2012

Divide by Zero: Weird Math in CMS Clinical Quality Measure (CQM) Criteria

From the CMS "Medicare Electronic Health Record (EHR) Incentive Program - ATTESTATION USER GUIDE For Eligible Professionals (EPs)" (warning: large PDF), page 41/64:

... Step 25 – Core Clinical Quality Measures (CQMs 1 of 3)

EPs must report calculated CQMs directly from their certified EHR technology as a requirement of the EHR Incentive Programs. Each EP must report on three core CQMs (or alternate core) and three additional quality measures. If one or more core CQMs is outside your scope of practice, you will have to report on an equal number of alternate core CQM(s).

If the denominator value for all three of the core CQMs is zero, an EP must report a zero denominator for all such core measures, and then must also report on all three alternate core CQMs.

If the denominator value for all three of the alternate core CQMs is also zero an EP still needs to report on three additional clinical quality measures. Zero is an acceptable denominator provided that this value was produced by certified EHR technology.

Now, while I had an "800" in the math section of the SAT, where I believed that a fraction with a denominator of zero had a value of either infinity or 'undefined', that was many moons ago. Perhaps my knowledge of mathematics is now obsolete...

Wait - I tried this simple program on an old Microsoft MS-DOS GWBASIC interpreter, ported ca. 1981 to the Intel 8086/88 from Bill Gates' original 8080-based MBASIC, that I have laying around on my PC:

20 LET Y=X/0
40 END

and got this warning/error message, right from Bill Gates:

"Division by zero"

and the answer: 1.701412E+38 (infinity in the 8/16-bit world from where GWBASIC sprang).

So ... allow me to say I find CMS math just a bit puzzling.

Wait ... now I understand.

Infinite quality! :-)

But thank heavens the zero denominator is only accepted when produced by 'certified' health IT.

Uncertified health IT is liable to produce a denominator of "i" (that is, the square root of -1).

-- SS

Addendum: since I am not a government math genius, I checked with Wikipedia:

... A common fraction (also known as a vulgar fraction or simple fraction) is a rational number written as a/b or \tfrac{a}{b}, where the integers a and b are called the numerator and the denominator, respectively.[1] The numerator represents a number of equal parts and the denominator, which cannot be zero, indicates how many of those parts make up a unit or a whole.

-- SS


This post is partly satire. I was a day late for April 1 but...

-- SS


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