The “Preferred” Measurement System of the US

By The Metric Maven

Bulldog Edition

The object to the left is an everyday thing, but it is making a clear statement about the designer’s measurement preference. It may not be apparent what the measurement preference is to you. It might not have been to me had I not read The Design of Everyday Things by Donald A Norman (suggested to me by Sven). The design of even the simplest of objects is done in a manner that provides information on how the designer intends them to be used. A person will unconsciously take an intended design clue, and use an object as intended. Knives are provided with handles, and one doesn’t stop to think which is the best end to hold in one’s hand after early experience and instruction in childhood. Norman cites research which argues there are at least 30,000 everyday things around us, and decreases the number to 20,000 to state: “Suppose each everyday thing takes only one minute to learn; learning 20,000 of them occupies 20,000 minutes —333 hours  about 8 forty hour work weeks.” We have a considerable amount of time invested in learning about our everyday things. When we encounter a can opener, or a scissors, or a potato peeler, we generally know exactly what to expect, how to hold it, and how to use it. One way that a designed object signals how it should be used, is to design it so the ways it may be used are limited, this is called affordance by Norman.

When I worked on the design of televisions, I immediately ran into the idea of affordance. A television motherboard and its chassis were dropped off in my lab, but about seven cables had been disconnected. I protested that it was all apart, and was calmly told by a technician  that all the plugs would only go into one place on the motherboard. Indeed, they did, and I was impressed that because of this affordance, I couldn’t make a mistake.

The affordance of the TV motherboard was essentially foolproof, but often designers can’t restrict a user that much, and the affordance involves only discomfort or a subtle tactile clue. Donald Norman offers this:

Take another example of good design. My felt-tipped marking pen has ribs along only one of its sides; otherwise all sides look identical. Careful examination shows that the tip of the marker is angled and makes the best line if the marker is held with the ribbed side up, a natural result if the forefinger rests upon the ribs. No harm results if I hold the marker another way, but the marker writes less well. The ribs are subtle design cue—functional, yet visibly and aesthetically unobtrusive.

Norman also shows numerous door handles as examples. If we see only a push plate on a door, we have no other choice but to push to open the door. A handle which one can readily grasp cues us that we pull to open it. This brings us back to the measuring cup shown above. Its design is pro-metric, as the metric graduations are facing a person’s eyes when it is held with the right hand. About 70-90% of the worlds population are right handed. Right handed Americans using this measuring cup, would find it uncomfortable and unnatural to place the handle on the left. The measuring cup shown is from the period when the US pretended it might go metric. Measuring cups of this same type, which are currently sold in the US, are all designed so that the imperial graduations face one’s eyes when held with the handle on the right. One of mine is shown below:

Common American Measuring Cup

Measuring cup designs have improved since the 1970s. Some of the ones I now own are “top readable” and only sold (unfortunately) at product parties. Dual scale is always a hindrance to metric adoption, but this set of top reading measuring cups are the best I have encountered.  I have visited many cooking stores and looked online, but have yet to find metric-only measuring cups and measuring spoons. The measuring cup shown below appears to have eliminated a right hand bias as well as being easy to read. Now if I could just purchase a metric-only one.

Top Read Measuring Vessel with Clear Metric Graduations
Left Handed Ruler

The design of common measuring cups is but one example of subtle anti-metric bias in our everyday things. In a previous blog I mentioned that the design of American “metric” rulers hinders their use because of the presence of a centimeter-millimeter dual unit scale, and the rounding of the origin end of one particular metric scale. The origin of the inch scale is placed on the square end, which is much more natural for measuring. For about 10% of our population, which are left-handed, the current dual scale measuring cups are adequately designed for metric use. On the other hand both metric and inch ruler scales  have equally low affordance for left-handed people. Left hand rulers exist which have the numbering from right to left to increase the ease of use by a left handed person.

My father gave me an expandable wrench for my last birthday, which has mm markings on one side, and had inch on the other (yes, I ground off the inch scale). If one holds the wrench as a right handed person would, the inch scale faces your eyes. On the opposite side is the metric scale, which has low affordance for a right-handed person. The wrench is nice because it allows one to immediately see what size a bolt head is in mm, but it is very cumbersome for me to use, as I’m right handed.. I have a better understanding of what left handed people deal with on an everyday basis in our world.

Expandible wrench designed with an affordability preference for inches (click to enlarge)

These examples point to the fact that a preference for imperial measures is designed into our US tools, and US everyday things. But I’ve been assured by non-binding legislation that the US prefers metric measurements. Here is some background:

The Omnibus Trade and Competitiveness Act of 1988 was signed into law by Ronald Reagan. It amended the Metric Conversion Act of 1975, yet didn’t have the word metric in the title of the legislation. President Reagan and Congress apparently were concerned that the voluntary nature of the Metric Conversion Act of 1975 was not clear enough.

Section 3 of the Metric Conversion Act of 1975 is amended to read as follows:

SEC. 3. It is therefore the declared policy of the United States

(1) to designate the metric system of measurement as the preferred system of weights and measures for United States trade and commerce;

(2) to require that each Federal agency, by a date certain and to the extent economically feasible by the end of the fiscal year 1992, use the metric system of measurement in its procurement, grants, and other business-related activities, Except to the extent that such use is impractical or is likely to cause significant inefficiencies or loss of markets to United States firms, such as when foreign competitors are producing competing products in non-metric units;

Well, it has been the case since the 19th Century, that switching to metric is always “impractical” in the US. Apparently there was much concern among our legislators that we have an exception: “such as when foreign competitors are producing competing products in non-metric units;” Apparently Liberia and Myanmar (the last two non-metric holdouts in the world) might flood the US (and the world?) with non-metric products, and thereby destroy what’s left of our uncompetitive non-metric US economy. Thank you President Reagan and Congress for the foresight to see the threat and protect us from the economic danger posed by these two tiny countries, and making an exception. Clearly the 1992 date was meaningless and arbitrary. It made it look like the government was taking action, when in fact it was not. Metric is 21 years past the expiration date for becoming “preferred.”

One can easily see how “preferred” metric is in the US simply by inspecting the design of our everyday things and everyday tools. The legislation is feckless, and crass hypocrisy. It is in line with the strange belief that if we cling onto the trappings of our past, the future may be indefinitely postponed. This emotional response, written in legislation, only postpones the day when reality intervenes, and forces Americans to realize that fantasy is no match for reality. I’m not willing to wait another 150 years hoping America will come to its senses. We need legislation that compels industry to design and make available true metric products, during a short compulsory switchover by industry, government, and education to metric. What we have now is legislation celebrating the the metric system as the preferred system of the future and makes sure it will always remain so.

Related Essay:

The Invisible Metric Embargo

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.

The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.

The third book is not of direct importance to metric education. It is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

10 thoughts on “The “Preferred” Measurement System of the US

  1. I’m in the middle of installing engineered plank cork flooring – and for the first time have a suitable metric rule for the job. (The longest tape metric tape measure I could find on my last attempt was 3m – not long enough for any serious job)

    Turns out the planks are 295 x 905 mm – native metric. The instructions include both systems – but metric is given first! Looking at the other languages – all use metric only.

    There is a fair amount of accuracy needed for this job – there has to be an expansion gap – but too much gap and the molding won’t cover. I’m once again finding carpentry work in particular is well suited to mm resolution – and while I always run my mental math calculations twice on projects like this – I’ve not been able to make any errors – and there are enough calculations that working with fractions would have moved me to paper.

    • Some years ago I encountered boxes of floor tiles originating in Brasil. They were marked as 20 cm squares but also for the US market as 8 inches. 20 cm is not 8 inches. I measured the tiles and they were 20 cm on a side, not 8 inches.

      if someone did a calculation on the number of floor tiles they needed to buy based on 8 inches, they would be off, as the difference between 20 cm and 8 inches accumulates. The floor tiles are meant to be fitted together with no gap and the 3 mm difference adds u9 to over a centimeter every 4 tiles (12 mm). By the time you come to the end of the row, you have used more tiles then the 8 inch calculation would show.

      You may run short and have to return to the store to buy more or if special ordered have to reorder and hope you can get the ones you already bought.

    • I found that in South America and Asia, tape measures tend to be dual, with inches on the top and millimetres on the bottom. This would appear at first glance as being awkward for a metric user, but it isn’t. On a visit to Mexico in 2012, I was given a demonstration as to how friendly the metric on the bottom really is and that the inch markings are 100 % ignored.

      The person demonstrating how the tape is used, set the right angled stop at the end to the edge of his desk and proceeded to pull the tape to the left with his left hand. Not a problem for a right handed person. This left his right hand free to mark off dimensions at preferred distance on the tape.

      Since most people are right handed it would be difficult for them to use a dual tape and use the marking on the top, as they would have to use their left hand to do the marking and right handed people have difficulty writing with their left hand.

      Which is easier, to hold a measuring cup in your left hand and pour into it or fill it with your right, or vice versa? It may be easier to scoop with it holding it with your right, but scooping is not preferred, as you can introduce a contaminate to your product and make a mess. Do you really want to have part of your ingredient sticking to the outside of the cup? Do you really want to dip a cup that had an egg in it or milk and into your sugar bag?

      It may be easy and the lazy way to fill the cup by scooping, but it is not the preferred way. So, it is much easier to fill the cup the right way by holding it in your left hand with the metric markings facing you and pouring your ingredients into it.

  2. Metricmaven has made another error, one he refuses to correct so it is important that readers be made aware of his errors.

    Metricmaven shows a picture of a dual measuring cup. He claims it is in imperial units, but something is seriously wrong. The cup markings show that 2 cups equal 16 ounces equal 1 pint.

    In imperial, this is not true. In imperial 20 ounces is a pint, not 16 and thus one cup is 10 ounces or 284 mL, not 240 mL as is in a USC cup.

    I don’t understand, and possibly never will understand why Metricmaven continues to make the same error over and over again. That constitutes ignorance. He should know better and refusing to just turns people off to his comments

    • Say it isnt so Maven!?! Can this be true, are you posting bad info????

      • Some thrive on negativity….not I, its all good Maven, keep it up!!!!!

    • Calling USC Units and UK Imperial both imperial seems to make people less upset than calling them English units for some reason. Maybe saying British units or American units?

      I feel planting seed in a vegetable bed or small plants using -cm- is visually simple enough without use of -mm scale.

  3. Pingback: The Metric Philosophers | The Metric Maven

  4. I appreciate this website, as I am an American metrication proponent. There is a lot of good, and thought-provoking, information here. I must take exception, however (as other readers have) to calling U.S./American customary units “imperial.” They are not. Both the U.S. customary units and British imperial units are based on English units of measure, of course, but in America we standardized on certain units that in some areas differ from the standardizations of the later imperial system. Liquid measures of volume are probably the most obvious area of difference. Please do stop referring to U.S. customary units as “imperial.” Otherwise, and carry on!

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