Measuring things, again


DB responded to my entry about “Just because it’s not easy to measure …”,  which gave me mixed feelings. I am thankful that he acknowledged that his statement was not what he meant but I must admit that I am in awe of DB – hence I was uncomfortable that he would apologize.

Since I follow his blog, my first instinct was to comment that I agreed with the comment made by “Curious” in the entry that had the quote. But DB didn’t respond to Curious’s comment so I left it alone.

In my field of laboratory medicine, I will continue – having started about 20 years ago – to advocate for measuring everything that’s important. This includes not just measuring the easy things like precision and bias but also the difficult things like rare interferences or user errors.

I added the quote from DB, because it’s important for guidelines. With healthcare reform, we can expect more rather than fewer guidelines in part fueled by the 1.1 billion for comparative effectiveness research.  Obama said:

“The point is we want to use science, we want doctors and medical experts to be making decisions that all too often right now are driven by skewed policies, by outdated means of reimbursement, or by insurance companies.“

I became aware of this from a Dr Rich entry. Comparative effectiveness research will be based on data, analyzed to yield measurements, which will turn into conclusions and recommendations. There is a famous statistical example about how difficult it is to measure things. Youden (1) compiled 15 different estimates of  the astronomical unit from scientists who estimated that quantity over the years 1895–1961. The confidence interval constructed by every scientist did not overlap the confidence interval of his predecessor. The difficulties are only greater in medicine. Just getting agreement on definitions is important as I cited an example for side effects of prostatectomy where urinary incontinence was defined as using greater than 3 pads per day implying that less than 3 pads per day = continence. Maybe urologists could agree with that definition, but I don’t think patients would.


 Youden WJ. Enduring values. Technometrics 1972;14:1–11.


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