The ‘Argument of Twelves’ and the Metric System

The fact that we have 12 inches in a foot isn’t a good reason to reject the metric system. Image from arielrobin on Pixabay.

(Sorry for the long lag between posts. I had some things going on in my life that required my full attention. Things are pretty much back on track. Thanks for your patience.)

Awhile back I was fulfilling my role as a scientist ambassador at the Bradbury Science Museum here in Los Alamos, NM. (This mostly consists of setting up various measurement activities and chatting with visitors about the advantages of the metric system for a couple of hours on the occasional Saturday.)

One day I realized that a man was starting to pace back and forth in front of me. Even though I wasn’t yet done prepping and I sensed this gentleman was about to go on the attack, I went ahead and said, “People are dying in this country because we don’t use the metric system in this country.”

“I don’t believe you,” he replied.

Even the Centers for Disease Control recommends strict use of metric units for liquids. (Pills are measured in grams, or a fraction thereof, already.)

I then handed him the 2016 Top Ten Patient Safety Concerns for Healthcare Organizations report put out by ECRI [Emergency Care Research Institute]. Number seven on the list: “Medication Errors Related to Pounds and Kilograms.” It advocates for only using metric system units (i.e. kilograms for weight) to reduce dosing errors since most medications use weight to determine the correct dose. It’s reason is simple: There are about two pounds in a kilogram. Doctors and nurses are schooled in the metric system but have to bounce back and forth between metric and U.S. customary units to communicate with their American patients. If they mix up the two, they might give the patients half the dose they need (potentially rendering it ineffective) or twice the amount (read overdose).

Using metric system units for medicine has also been recommended by multiple health organizations including the Centers for Disease Control. (See the above image)

The gentleman reviewed the report and since—I assume—he could no longer argue on that particular point, he launched into what I’ve now dubbed “The argument of twelves.”

The Argument of Twelves

The argument goes something like this: If you are working with a group/set of 12s, then your factors are 1, 2, 3, 4, 6, and 12; but if you are working in the metric system, your factors are only 1, 2, 5, and 10.

I consider this to be a specious argument since (and please, but nicely correct me if I’m wrong) we don’t really measure a lot of things by twelves. Sure, a foot has twelve inches and there are twelve months in a year. (Apparently eggs are sold by the dozen—according to the New York Times—because eggs were a penny each and there are 12 pennies in a shilling. Selling eggs by the dozen meant, as a vendor, you didn’t have to make change.) However, there isn’t much else I can think of that comes in twelves except a gross of 144 items (which is 12 multiplied by 12). You can’t really cite time because military/Zulu time uses a 24-hour clock.

If we actually had 12 ounces in a cup and 12 cups to a gallon and 12 ounces in a pound and 12 yards to a mile, then I would understand that counter argument. (In reality, there are 8 ounces in a cup, 16 cups and 128 ounces in gallon, 16 ounces in a pound, and 1,760 yards in a mile…plus 36 inches or 3 feet in a yard and so on.)

But, when it comes to everyday measurement, we really only divide up inches, months, and eggs into twelves. I don’t think that’s enough reason to reject using the metric system.

However, I’ve found after seven years on this project (the anniversary of which was the day before yesterday), if people are threatened by the idea of changing to the metric system—for any number of reasons—they will latch onto whatever immediately comes to mind to reject it.

Around the time that the man was winding down his argument of twelves, some other—more open-minded people—approached me and I turned my attention to them.

I’ve said many times that, when it comes to this issue, there are probably 10-20 percent of people who already love the metric system and there’s about another 10-20 percent who are completely opposed to it.

It’s my plan to focus my attention on the 60 to 80 percent who don’t realize we have a problem in this country and are open to learning about it. Maybe action will eventually occur. That’s my hope. If you want to become more involved, let me know at milebehind@gmail.com.

In a closing note: I realize that some people ascribe a historical and religious meaning to the number 12, but we don’t have to limit the number of members on a jury or the number of apostles due to the metric system so let’s not shoehorn that number into our measurement system unnecessarily.

Plan for another post in September.

Thanks for getting this far,

Linda

Medicine and the Metric System

Allow me to present my main point upfront: we are endangering our health by not adopting the metric system in this country.

Prescriptions are written in metric units. Conversions (and possible errors) are made at the pharmacy.

Doctors write prescriptions in metric units. Conversions (and potential errors) are made at the pharmacy.

Let me offer up a couple of examples that hopefully makes this clear. It’s important to understand that the medical field depends on metric units (as does most of science, for that matter). If healthcare workers talk in metric units and the public at large rely on U.S. customary units there is bound to be confusion and misunderstandings. That’s best avoided where your heath is concerned since the consequences could be dire.

Metric unit dosing is more precise

Last year Pediatrics (Official Journal of the American Academy of Pediatrics) published an article called “Unit of Measurement Used and Parent Medication Dosing Errors.”1 One of the article’s bottom lines:

Parents who used milliliter-only unit made fewer dosing errors than those who used teaspoon or tablespoon units. Moving to a milliliter-only standard could reduce confusion and decrease medication errors, especially for parents with low health literacy and non-English speakers.

While a minor mistake (whether too much or too little medication) might not make a huge difference for an otherwise healthy adult, these errors can be magnified for babies or those whose health is already compromised.

Most of our teaspoons and tablespoons are meant for eating, not dosing

No on should use "silverware" as substitutes for measuring teaspoons and tablespoons for medicine to avoid dosing errors.

No on should use “silverware” as substitutes for measuring teaspoons and tablespoons for medicine if they want to avoid dosing errors.

Another issue brought up in the piece was that the use of teaspoon and tablespoon employed for liquid medicines “may endorse kitchen spoon use.” I don’t know about you, but I have three sets of measuring spoons and many more spoons that I use for eating commonly referred to as “teaspoons” and “tablespoons.” The problem is, it’s the eating spoons that are often used to measure medicines. (Yes, I used to do that too, without even thinking about it.) If you have a dosing cup with only milliliters, the potential for confusion is greatly reduced.

As if that’s not bad enough

Even your actual measuring spoons aren’t as precise as you think they are. At one point I came across information indicating that up to a 20 percent variance is allowed. Again, that 20 percent could cause dosing errors. In researching this article I came across a page called “Cooking for Engineers” with the post:

I’ve got three sets of measuring spoons, and their measurements differ from each other, up to 1/4 teaspoon! Is there a way to know which (if any), are accurate?

The suggestions that followed involved scales and the temperature at which one should measure the water used to determine volume. Too bad no one suggested going metric.

Additional endorsement of the metric system for health reasons

I also have a document from the Institute for Safe Medication Practices (ISMP) called 2014-15 Targeted Medication Safety Best Practices for Hospitals2 . Two of its best practices mention sole use of metric system units.

Best Practice 3: Measure and express patient weights in metric units only.

The rationale:

Significant medication errors have occurred when the patients’ weight is documented in non-metric units of measure (e.g., pounds) and it has been confused with kilograms (or grams). Numerous mistakes have been reported when practitioners convert weights from one measurement system to another, or weigh a patient in pounds but accidently document the value as kilograms in the medical record, resulting in more than a two-fold error.

Best Practice 5: Purchase oral liquid dosing devices (oral syringes/cups/droppers) that only display the metric scale.

ISMP has received more than 50 reports of mix-ups between milliliter (mL) and household measures such as drops and teaspoonfuls, some leading to injuries requiring hospitalization.

Beware teaspoon and tablespoon instructions on prescriptions

Almost uniformly, prescriptions are written in metric units. However, if you pick up a liquid prescription and the dose on the bottle is not metric (and in reads teaspoon and tablespoons), the pharmacy has had to make a conversion. Where there are conversions, there is the potential for mistakes.

In addition, one of the top six recommendations in the 15th annual report of the National Coordinating Council for Medication Error Reporting and Prevention3 includes a “Statement of support for use of the metric system to dose medications.”

Advocate for the metric system and help make the country a healthy place!

Thanks,

Linda

Notes: The article itself requires a subscription http://pediatrics.aappublications.org/content/134/2/e354.full.pdf. However, a summary is located here: http://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/Reducing-Medication-Dosing-Errors-by-Ditching-Teaspoons-and-Tablespoons.aspx.
2 http://www.ismp.org/tools/bestpractices/TMSBP-for-Hospitals.pdf
3  
http://www.nccmerp.org/sites/default/files/fifteen_year_report.pdf