I love the proverb, “What gets measure gets managed.”

This principle often gets applied to business situations. It can mean that simply examining an activity changes the activity by forcing you to pay attention to it. It can also mean that producing measurements about the activity gives you a handle on it, a way to improve it. If you start adding up your sales volume every month, it gives you a basis for saying, I’m not generating enough revenue, I need to do more selling.

But I’m interested in knowing the source of that quotation. It often gets attributed to management expert Peter Drucker, but I’ve never seen an actual reference that proves he said it.

This blog post will serve as an ongoing investigation of this quotation and might be updated from time to time as new information comes to light.

Here are some popular forms of the quotation:

“What gets measured gets managed.”

“What doesn’t get measured doesn’t get managed.”

“What gets measured gets done.”

“To measure is to know.”

However, I haven’t been able to find any reliable reference that traces any of these forms to Peter Drucker or any other original source. It’s possible that these are nothing more than memes that have caught on and keep getting passed around.

So far, the most likely source of this idea, if not in any of these popular forms, is William Thomson, the Scottish physicist also known as Lord Kelvin. According to the Encyclopaedia of Occupational Health and Safety, by Jeanne Mager Stellman (page 1992), Kelvin said in his May 3, 1883, lecture on “Electrical Units of Measurement” (Popular Lectures, Vol. 1, page 73):

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.

That might be the best we can do in tracking down the source of this bit of management wisdom.

Some people probably think it doesn’t matter whether we get these kinds of things right or not. But in his story about researching this same Lord Kelvin quote, James Heywood of patientslikeme makes some good points about the value of checking primary sources.

ARB — 2 Dec. 2012