Is perfect the enemy of good?

Recent experience in France and Greece and a comment last week by Charlie P on this site has prompted us to ask if it would be better if supporters of metric measures were less pedantic.

In January 2014, UKMA wrote to James Harding, then Director of BBC News and Current Affairs. The letter included the following:

“You will probably be aware that SI, commonly known as the metric system, is used around the world, and is the primary system of measurement in two hundred or so countries. Rules for SI are agreed internationally, and if these rules are followed, then the information will be widely understood – “50 km” has the same meaning, not only in languages that use the Latin alphabet, but also in, for example, Greek, Russian and Arabic and in Hindi, Mandarin and Japanese.

The section of the BBC news style guide headed “Weights and measures” has recommendations that depart from the internationally agreed rules.”

Harding took the trouble to provide a carefully considered reply:

Harding’s reply dated 11th February 2014

His third and fourth paragraphs are particularly relevant to this article.

We were reminded of this correspondence during a recent visit to France. We encountered several instances of less-than-perfect examples of metric use, including this on a pack of green beans:


An Englishman, John Wilkins FRS, may be the father of the world’s decimal system of measures. But France is definitely its mother. France, surprisingly, took almost as long to adopt the metric system as the UK is taking, but the job was largely completed over a century ago. If a rather relaxed attitude to the rules of SI is found in France, then perhaps we should not be concerned when this happens here, as suggested by Mr Harding.

And it is not only in France that SI rules are occasionally ignored. In Greece last week, we noticed an abbreviation for ‘litre’ rather than a symbol and, oddly, in the Latin not the Greek alphabet:

Charlie P went further in his recent comment on this site:

“What is the point in being pedantic about this when the system is impossible to comply with in all cases … Better, I think, to lobby for a more user-friendly system, and perhaps then it will also be better received.”

A more user-friendly system. Such as?

What do readers think?

The heading of this article is a variant on a well-known phrase which is considered in this Wikipedia article:

The use of measurement units in the media was considered in a post on Metric Views on 2015-01-16. This provoked a lively debate with 40 comments.

17 thoughts on “Is perfect the enemy of good?”

  1. What can be more ‘user friendly’ than everyone using the same units and symbols?

    Here is one abbreviation that came up on ITV a few weeks ago ‘mlbs’. In context it was not difficult (if you happened to know SI), but why? Used one day out of 365 days a year.


  2. Labels on food are things that set good (or bad) examples for the public at large, as is also true of the media, and we should be harder on them than on the general public.

    In the US, those labels would be non-compliant. The FTC rules for the Fair Packaging and Labeling Act (FPLA) allow the unit word to be spelled out in full or the proper SI symbol (including case, no punctuation or pluralization). A list of the proper and allowed symbols are given in “these and no other” language Part 500.23). More leeway is allowed in the Customary declaration, case, pluralization, and punctuation are optional although NIST “prefers” an invariant symbol form (part 500.22). Errors may still be found, but when they are pointed out and the manufacturer investigates, he finds there are clear guidelines from the governing Federal agency and he is non-compliant.


  3. If only teachers, especially those at the nursery and primary level, were far more pedantic then we would not be experiencing problems like inkorrect symbols (Kg) and pluralization errors (kms). In school tests and external exams the marking schemes should allow for giving credit to candidates who do leave a space between the numerical value and the symbol ( 12.34 mW, not 12.34mW). And also give credit for writing numerical data/answers in the recommended format (12.345 678 not 12.345678).


  4. Brian AC:

    What does mlbs mean? millipound seconds?

    I agree 100 % with Mary. On other forums on the metric system I have repeatedly posted that SI is incorrectly taught in schools world-wide, thus no one learns the proper symbols and how important it is to get them right and how the prefixes are not taught correctly so the right prefix is chosen to put the number in a sensible range and end the need for counting words. Millions of kilometres is wrong and should be stated as gigametres. But the only way for the correct choice to be made is with proper education. Otherwise people are only guessing.

    Proper education starts at the beginning and that has to come from the BIPM itself. It needs to create a teaching method that can be used in all schools world-wide.


  5. The problem with teachers, who in the UK taught the teachers SI? I guess nobody. As always HMG makes a statement or passes a law and everything is supposed to miraculously happen.
    Firmly rooted in muddy water there never was, as far as I can see, any real program nor syllabus for the teaching of metric. I base this mostly on the lack of results and an almost unbelievable lack of knowledge and uptake of SI outside of industry.


  6. I think it is very important to not be pedantic, or you will drive people to use the system they see as less pedantic. People like units that they can relate to (or should I say, “to which they can relate”, to keep the pedants happy?). When signs are in kilometres, and car odometers are in kilometres, people will be comfortable with kilometres, not megametres (a word that even my spellchecker doesn’t recognise). Can you seriously imagine anyone in an everyday conversation saying “It’s two point five megametres from London to Moscow”? I certainly can’t imagine telling any of my friends that they really shouldn’t use centimetres, or that their email was incorrect because there wasn’t a space between the 72 and the kg (perhaps adding that therefore I didn’t understand them?). I would just be happy they are using metric, so I don’t have to get my calculator out. And finally, on that word “metric”, acronyms are user-unfriendly, especially if someone asks you what SI stands for, and they (or you) speak French badly, or not at all. How far do you think you would get if you asked a shop assistant anywhere on this planet “Can you give me the dimensions of that fridge in SI, please?”. You might get lucky and find you’re talking to a science undergraduate earning some beer money, but it’s likely you’ll get no further than if you had asked the question in the wrong language. And that’s because it /is/ the wrong language – for everyday use.


  7. Some countries do seem to have their idiosyncrasies when it comes to metric usage. The use of ‘kilo’ instead of ‘kilogram’ or simply ‘kg’ by street traders is common in some European countries. When it comes to leaving a space between a figure and ‘m’ or ‘km’ in a published text, it seems to be mainly the media in the UK that object. The argument used to be that the figure might end up being separated across a line divide from the metric symbol, making it look strange. Now that we have such a thing as a ‘hard space’, that argument is surely redundant. Another argument I have heard is that editors don’t like to waste space (!). I think the real problem is that Brits, both the general public and the media, are totally and utterly confused. In some places they regularly encounter metric, in others they still encounter imperial. I have always understood that metric is the country’s official system of measurement (and in the supermarkets that largely seems to be the case), but how can that be when road signs in imperial units hit you in the eye on just about every street corner? How does that square with metric being the country’s official system of measurement? My solution is for the country to move over to metric, which is after all what children are taught in school, and leave the details to sort themselves out. Space, no space. Symbol or abbreviation of the metric unit. That will all sort itself out in time. The imperative is to get rid of imperial units in national life. Britain will them settle down as a metric country in its own right. I’m sure it will (continue to) develop its own idiosyncrasies, but at least we will all be using the same system for measuring things.


  8. In truth, we need to strive for perfection. In the old school days, spelling of words and getting those words spelled correctly was important. Should we be pedantic or not pedantic when it comes to spelling and just let everyone spell words as they wish? Incorrect spelling in the past would have pointed to the incorrect speller as being stupid and nobody wanted to be labelled stupid so they put forth an effort to be correct.

    The same has to be true with unit symbols and prefix usage. SI is a language and proper communication in that language needs to be done correctly so there is no confusion and mistakes. Otherwise it is just plain and simply anarchy. Imperial and USC in the form of being “user friendly” has become a confused muddle and part of the reason that it is useless in science and engineering and that the world has chosen the metric system. We all sub-consciously value that which is organised, logical and perfect and disdain that which is not. So yes, we do need to be pedantic in this case. We need to make and keep the SI perfect to be a beacon of light for the whole world to be drawn towards in the world of measurement darkness.


  9. Daniel’s comment:2018-11-16
    A follow up: (i) “there” and “their” ; “your” and “you’re” ; just two examples and if you get them wrong, expect to be criticized. (ii) “Kms” and “km” ; “Mj” and “MJ” again expect to be criticized if you get the symbols inkorrect or wrong.
    I’ll also add: “11/16/18” and “16/11/18” there is an international standard format for writing the date, please look at the ISO website:-


  10. The hard, or non-breaking space is not always available; it depends on the character set in use both during entry and during display. It can also be awkward, or impossible to enter. Better that the number and units remain together without a space, than get spread over two lines, or split across two pages.

    If you use spelling as your argument for insisting on rigid rules for metric use by the general population, you have effectively destroyed your own argument. Spelling is very fluid and varies with time and place. The American spellings that some British people love to criticise are sometimes the same as British spellings from a couple of hundred years ago. The same is true of grammar. Dictionaries and grammars don’t define how language should be used, but rather they reflect common usage. So by the spelling argument, if “10Kms” is more commonly used than “10 km”, then that is what would appear in an SI grammar. Be careful what you wish for.


  11. @ Robert:

    If you use spelling for ‘not’ insisting on proper rules for the use of metric measurement, you are in effect saying that spelling doesn’t matter. Spelling, in English at least, is not as much fluid as varied. You are correct in saying that some American forms are older English forms, but both British and American usage are merely variants of the same thing. Within Britain, the British spelling will be preferred, though the American spelling will usually be understood too. An example of where the American spelling has ousted the British spelling is the word ‘program’ in anything to do with computers. But this is not the point. A teacher in the UK will always correct incorrect spelling. An applicant with spelling errors on his or her CV will not normally endear themselves to a future employer or increase their chances of landing a job where any form of writing is involved. How you spell and write, and your use of grammar, say something about you as a person. This is not quite the same with metric symbols in the UK, which is still in the process of transitioning to full metric usage. I have always argued that it is better to get the conversion process over and done with (scrap imperial once and for all in all interaction between government and the general public) and then to work on trying to get people to use the proper symbols. There are instances, perhaps on labelling in the shops, where an abbreviation such as ‘grs’ may be just as effective as the proper metric symbol (though it is hard to deny that it is three times as long). It is impossible to imagine that the entire population of the UK will ever be able to spell correctly, just as it is probably impossible to imagine that the entire population will ever use metric symbols correctly. But slowly increasing the number of people who do, with the obvious flexibility where flexibility does no harm, is surely a goal worth working towards. Otherwise, your argument is to perpetuate ignorance.


  12. @Jake: I’m not arguing for perpetual ignorance, and I agree with most of what you say. A teacher should of course teach whatever is considered correct at the time, and make sure the information has been taken on board, because they are providing a formal education. Much of that knowledge will continue to be used as taught, but also, as you recognise, people will adapt their behaviour according to circumstances and experience. There may be circumstances when people don’t follow the rules, because they don’t work for them, and one just has to accept that and not be pointlessly and annoyingly critical.
    Outside of formal lessons, being pedantic will just annoy most people, as it always does. It is unlikely to have a positive effect. That goes for both English grammar and SI grammar.


  13. @ Robert:

    Yes, people may adapt their behaviour according to circumstances and experiences. But to stick to the few comparisons I have been making, people don’t normally adapt their spelling according to circumstances and experience, unless they are using an agreed convention or a mobile phone. If u r with me. The advantage of using proper metric symbols is that they are independent of language and are immediately understandable whatever language you speak. The Italians write km/h for kilometres per hour despite the fact that there is no letter ‘k’ in the Italian alphabet (the letters j, w, x and y are also not part of the Italian alphabet and appear only in loanwords). I am sorry you feel it is being ‘pointlessly and annoying critical’ to expect people to spell and to use metric symbols the way they were taught them at school. As I have written before, once we are all singing from the same metric hymn sheet and imperial units have been consigned to the museum, there will be opportunity enough for creativity and flexibility if this is needed. An example of this from Spain is the use of ‘mtrs’ on road signs, an abbreviation of ‘metros’, instead of the metric symbol ‘m’. Personally, I do not care for it, but perhaps the Spanish authorities feel it is more visible than the symbol ‘m’. We use an ‘m’ to mean miles, which is of course exactly what it does not mean. The Americans at least write ‘mi’ to make a distinction from the metric symbol. You say teachers are providing a ‘formal’ education. But the whole of life is an educational process. Or do we all stop learning when we leave school?


  14. @Robert Indeed and kilometers work pretty well at the planetary scale anyway, I would kinda like to see the Pm come into usage in place of the light-year for astronomical scales though as we already have a perfectly good SI length unit based on a universal physical quantity that can be measured anywhere. To then confuse things by multiplying that same physical constant by the mean orbital period of a random ball of rock you know just for reasons seems kinda pointless to me.


  15. Seraphina985

    The whole purpose of using SI units is to pick a prefix that places the numbers between 1 and 1000, eliminating counting words and/or a plethora of zeros. Using millions, milliards, billions, billiards, etc along with kilometres is senseless.

    So, whereas the petametre would serve as the perfect replacement for the light year, once the value passes 1000 PM, then exametres, zettametres, yottametres, etc would be used. If the distance is so large that we run out of prefixes then powers of 10 exponents would be used with metres. But this would not be necessary as the diameter of the observable universe for now is 8.8 × 10^26 m or 880 Ym, which is completely covered by all existing prefixes.

    The BIPM is considering adding four more prefixes to the list.

    A proposal lodged with the International Bureau of Weights and Measures (BIPM) in Paris recommends new names—ronna and quecca—as prefixes for 10^27 and 10^30, respectively. They would be joined by their microscopic counterparts, ronto for 10^?27, and quecto for 10^?30. If approved, the new terms could be formally introduced in 2022. They would be the first prefixes added since 1991.

    Once done, it will be way past our lifetimes before there would need to be a use of exponents due to a lack of proper prefixes.


  16. Amazon’s package labels … Another inkorrect symbol ‘0.5 Kgs’.
    Today I told Amazon the correct symbol for the kilogram, ‘kg’
    [The person I spoke to on the phone – when asked, didn’t know the correct symbol, she was going to look it up on their website].

    I’ve no idea how long it’ll take for this error to be sorted out, that’s if they take the trouble to correct it.
    It might be the labels for Amazon products sent out to addresses are produced by the carriers.
    When I spoke to the person from Amazon – I said it’s deplorable and disappointing that an international company like Amazon is unable to get the international symbol for the kilogram correct.


  17. Interesting thread.
    I live in a country which comprehensively changed to the metric system – Australia – apart from the usual bugbears of screen sizes in inches, Tyre pressure in psi, etc.

    I think it’s really important to remember the Golden Rules of Metrication:
    1. ‘Keep it simple, stupid’. So, if a unit is comfortable for most people, and it’s metric, you’re halfway there. Others rail about using the centimetre or centilitre—who cares? At least it isn’t using inches or ounces. Everyone knows 15cm = 150 mm..with or without spaces in the right place! The war on the centimetre seems such a waste of energy.
    2. Resist pedantry, or you lose their hearts and minds. Insisting on calling a tonne a megagram turns people off. Also, it is so close to the old 2240 lb ton, why annnoy people you’rer trying to win over?
    3. ‘Baby Boomers – stop using imperial measurements’. I am one. My generation behaves like old sticks-in-the-mud. You pass on bad habits. Stop being such old fogeys.

    I am proud of the way Australia did it. It was done with consensus, practicality, and with a forward-thinking mindset. The only blot on the horizon is the river of old units that emanate from the US and – to a lesser extent – The UK (or,from what I see happening, the Disunited Kingdom)

    Fortunately, we don’t have any parliamentarians mandating the use of mediaeval units.


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