An interesting article about metrication appeared in the Daily Mail Online recently, describing the current situation reasonably well – but arguing that the current British mixture of metric and imperial measurements is actually a good thing since it enables people to use the units “most apposite for the job in hand”. As this argument is seductive but utterly misconceived, it deserves to be taken seriously and rebutted.
MetricViews is not normally an admirer of the Daily Mail, a middle-market, tabloid national newspaper, which is well known for its populist, Eurosceptic, right wing stance on most political issues. Its audited circulation is 2.1 million, making it the UK’s second most read daily paper. In the past it has regularly used the metrication issue in its campaigns against the European Union. It was therefore pleasing recently to read a comparatively balanced article on metrication in its online edition – albeit that its author came to a wrong-headed conclusion. MetricViews welcomes any constructive contribution to the debate and we therefore provide this link to the article. We answer it below.
The article argues that British people “mix and match, using what suits us best and what seems most natural,” and the main points made (explicitly or implicitly) can be summarised as follows:
1. Most people aged 35 – 55 are “bilingual” when it comes to metric and imperial
2. Some imperial units (such as the pint and the mile) are inherently more convenient than metric alternatives
3. People should be free to use the units they prefer
4. Prosecuting people for “selling a pound of bananas” is madness
5. Inconsistency in newspapers doesn’t matter
None of these statements is valid, so let us examine them in turn.
1. It is probably true that some people aged 35 – 55 are “bilingual” (in the sense that they can easily visualise and manipulate both metric and imperial units) – but they are exceptional. What is far more common is that people in this age group do not have a secure grasp of either set of units. As metric units did not become mandatory in the school curriculum until 1974, most people aged over 50 will not in fact have been formally taught the metric system. They will of course have become accustomed to buying petrol and cooking oil in litres, but may well not know that there are 1000 litres in a cubic metre – let alone 100 hectares in a square kilometre. Similarly, anybody aged under 45 will almost certainly not have been formally taught the intricacies of imperial measures, and most will not have a clue how many feet there are in a mile or pounds in a hundredweight.
2. There is no evidence that the pint and the mile are more convenient than the litre or the kilometre. It is absurd to argue that half a litre of beer is too little and that a pint (presumably imperial – not US) is “perfect” (pace George Orwell) – the difference (68 mL) is only 12% and would scarcely be noticed in a brim-measure glass with a full head. Countries that use kilometres do not find them inconvenient – why would they? Obviously, it is simply a matter of what you are used to.
3. Traders should certainly not be free to use the units they prefer. It is fundamental to consumer protection that there should be a standard set of weights and measures that can be checked and enforced and which everybody is obliged to use. Otherwise, it is not possible to compare value for money of goods priced in different units. This leads to market breakdown – to the detriment of both customers and honest traders.
4. Leaving aside the fact that nobody has in fact been prosecuted for selling a pound of bananas (the trader was actually done for using illegal scales), if laws are not enforced, they will be ignored. While obviously enforcement should be done in a sensitive and proportionate manner, the sanction of prosecution must remain to be used as a last resort against traders who deliberately flout the law. The consequences of non-enforcement can be seen in many street markets where it is impossible for the customer to find out the unit price (i.e. per legal unit) of fruit, vegetables, meat and fish on sale.
5. People are influenced by and even copy the media. It is therefore incumbent on responsible journalists to set a good example – otherwise bad practice will be perpetuated. The random mixing of incompatible units destroys any sense that units form a logical and coherent system (which incidentally reflects the physical world). This last point may be lost on the less science-aware journalists, but they should also reflect that, if they want their readers to make sense of their reports, it is important to use measurement units that are compatible with each other. For example, in this sentence, “the aircraft was flying at 10 000 feet when it crashed into the 3500 m mountain”, the reader would struggle to know whether the pilot nearly cleared the mountain. Or if the banner headline tells us that petrol now costs £6 per gallon, and the ensuing report tells us that this resulted from the the VAT increase of 3p per litre, how can the reader work out the percentage increase? And as for barrels of oil…..
As the Mail journalist admits, many of his colleagues cheerfully ignore the recommendations of their papers’ respective style guides and just continue to use the units with which they personally are familiar. This is actually thoughtless, lazy and sloppy journalism and is a disservice to their readers and listeners. The article is an ingenious attempt to justify and rationalise this unprofessional behaviour. It doesn’t wash.
(See also our earlier article http://metricviews.org.uk/2007/10/whats-wrong-2-systems/)