What Does it Mean to Measure Twice, Cut Once?

Last week I was appreciating some of our old podcasts and video interviews with lean practitioners. Our interviewer Ron Pereira always likes to ask a series of short, rapid-fire questions. One of my favorites is, “What is the best piece of advice you’ve ever received?” Not only are the pieces of advice they share useful, the way they answer the question offers insight into the person.

This got me reflecting on pieces of advice I received over the years. Which ones have stuck with me? It may be recency bias resulting from the various home improvement odd-jobs I always seem to be doing, but “measure twice, cut once” stood out in my mind. It’s something my father repeated to me over 30 years ago when teaching me the rudiments of carpentry.

These days the most consequential measurements and cuts I make are not of wood or metal. They are of priorities, time and performance. For those of us who don’t work with cutting tools, what does it mean to “measure twice, cut once”? Certainly planning our day, goals and assigning the top priorities for our available hours is a form of measuring before we start cutting. When we take time to clarify and stratify a problem, go see, and work from data to select causes to tackle rather than jumping into problem-solving, this is a form of “measure twice, cut once”. But increasingly, I am not convinced that this is good advice in all situations.

What if there are little or no consequence to cutting twice? When we are dealing with irreversible decisions like cutting a piece of wood, it makes sense to “measure twice, cut once” because this can help prevent scrapping or reworking materials due to a wrong cut. But there are also cases where we can take action, evaluate the result, reorient and try again, with comparative small cost to “re-cut”. This is true for work with high uncertainty and high impact, such as research & development, experimentation, or efforts to enter new markets. It makes more sense to “measure, cut, measure” than to delay cutting until we have full certainty. The Lean Startup concept of releasing a minimum viable product and collecting user feedback is an example of this.

What if the cost of measuring is too high? Organizations that place a high personal price on failure are slow to adapt and change. An over-dependence on analysis leads to paralysis. One of the reasons the 5-day kaizen event format is so effective is that there is a series of measure-cut-measure-cuts or PDCA cycles that allow us make significant progress starting from imperfect information. When we create value stream maps, we are similarly unconcerned with precise measurement of data, because we want to look at the big picture, see the large system flaws and develop consensus on what to do. These things rely on the fact that there is plenty of obvious waste across a typical value stream to be kaizen-ed, and that “just do it” will take us a long way, even without precise measurement of the starting condition. When that is not the case, a thorough and analytical “measure twice, cut once” approach serves better.

What if we get different results each time we measure? A typical tape measure has a 1/16 adjustable tip that one uses to hook onto the edge of a piece of wood. It is there for a purpose. But it moves in and out by 1/16. What is the width of our saw blade? Are we looking straight down at the tape or from the side? Unless we understand how these elements work together, our measurement will be off. How do we know our measurements method is good enough? In continuous improvement terms, this is why we need to perform a MSA (measurement system analysis) to determine how much variation is inherent in our measurement process. “Measure twice” has little value if the result varies each time.

The advice to “measure twice, cut once” has saved me time and materials. Yet whenever a task is taking longer than expected, or I find myself doing rework, it seems to be because I have failed to heed or adapt this advice.

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