COSC, Chronometers, And The Omega Laboratoire de Précision

Great leap forward, or smoke and mirrors?

There are a number of different standards, independent and brand-administered, in watchmaking. Rolex, for instance, submits its movements for COSC certification but also regulates all of its watches to a maximum daily deviation in rate of -2/+2 seconds per day. Patek Philippe announced the Patek Philippe Seal in 2009, ending its decades-long use of the independent Geneva Seal. Omega and Tudor both test watches to the Master Chronometer standard, which is overseen by an independent agency – the Swiss Federal Institute Of Metrology. These standards all specify a value for maximum daily deviation in rate, which varies with the certification; a Master Chronometer, for instance, must have a maximum daily deviation in rate of 0/+5 seconds per day, compared to COSC, which specifies -4/+6.

COSC chronometer certification is based on the international standard ISO 3159, which is required for any watch to be called a chronometer. It is for instance required for Master Chronometer certification, which is not so much a substitute for COSC certification as it is an enhancement. (Timelab, which handles the Geneva Seal certification, also offers an Observatory Chronometer certification, which includes testing to ISO 3159 standards, as well as pressure, magnetism, and power reserve tests). COSC testing is therefore not really to a COSC standard so much as it is to the standard for wristwatch chronometers specified by ISO 3159, which was last revised in 2009.

ISO 3159 also an international standard – and a genuinely international one; the standard does not specify a country of origin. The standard specifies that the testing facility must be a “neutral official authority,” but at least theoretically, any watch company that wanted to call its watches chronometers, could do so as long as it met the requirements of ISO 3159. The catch is that you cannot certify your own chronometers – if for some reason it’s not possible to submit your watches to an established third party independent lab, then you’d have to either enter into agreement with an entity willing to perform the tests (and invest in the necessary equipment) or underwrite the establishment of such a lab yourself.

One of the criticisms leveled at COSC over the years has been that the so-called COSC standards are too lax, but I think it’s worth emphasizing again that they’re not COSC standards per se, but rather, ISO standards and there is nothing stopping a brand from regulating its watches to greater accuracy than ISO 3159 – with or without a chronometer certificate. If however you want to use the word “chronometer” then at some point an independent testing agency has to get involved. (I recently did a detailed breakdown of Master Chronometer certification for The 1916 Company’s Journal).

This brings us to the Laboratoire de Précision, announced by Omega earlier this year. The Laboratoire de Précision was announced as a testing center in two locations – one in Bienne and one in Villeret, both of which are also locations for Omega factories – and according to a press release from Swatch Group, “Measuring movements according to the standard ISO 3159 ‘Timekeeping instruments — Wrist-chronometers with spring balance oscillator,’ most commonly known as ‘chronometer,’ is one of the testing methods that the Laboratoire de Précision is accredited for.”

The Laboratoire de Précision is therefore a testing site (or two testing sites, at least so far) that provide chronometer certification per the standards established by ISO 3159. The LdP does not test to more stringent standards than COSC, nor to more stringent standards than any other lab which issues ISO 3159-standard chronometer certificates. The Laboratoire de Précision is therefore, or at least so it seems at first, identical in terms of testing standards to COSC. Are there any actual points of differentiation?

The major claim, as it turns out, is that the Laboratoire de Précision conducts more precise measurements. COSC testing measures values like gain and loss in rate once per day over a fifteen day testing regimen (the Laboratoire de Précision will also adhere to a 15 day testing period). Swatch Group’s press release states that measurements will be taken continuously, which presumably will result in a set of continuous data points rather than the discrete data points resulting from COSC measurements – a movie rather than a snapshot, you might say.

Swatch Group says: “At the Laboratoire de Précision, every beat of the calibre is measured and assessed, with a measurement accuracy ten times higher than the industry standard. The amount of data gathered during the tests, through industrial methods and big data analyses, will allow a brand or movement manufacturer to understand the chronometric performance of all its movements much deeper than ever before, while also helping to improve overall chronometric excellence.”

I’m not a statistician but it does seem intuitively obvious that continuous measurements provide more data – by definition, such measurements provide more data. If you see a curve showing temperature variations over the course of a day, for instance, you certainly have more data than if you only take the temperature at noon and midnight. What is less clear is the difference this will make to actual consumer outcomes. The end result from both COSC and Laboratoire de Précision testing is identical: a chronometer certificate stating that the movement tested, shows an average daily variation in rate of no more than +6 or -4 seconds per day, with a mean variation of no more than 2 seconds per day.

The second number – the 2 second per day maximum deviation in rate – is a measurement of precision. If the movement on average is +3 seconds per day as measured against a time standard, then its rate should vary from that by no more than two seconds per day; ISO 3159 is really more of a precision standard than an accuracy standard. The distinction between accuracy and precision is a universally accepted one in chronometry – for marine chronometers, for instance, precision is the priority since if you know the average daily rate variation it is easy to compensate in your longitude calculations for a gaining or losing rate, as long as the rate variation is low enough.

To take one very illustrious example, on its initial sea voyage John Harrison’s H4 marine chronometer was determined to lose on its rate by 24/9ths seconds per day. Over the 81 days of its passage to Jamaica, the chronometer lost a total of 3 minutes, 36.5 seconds but once the known daily rate variation – the losing rate of 24/9ths seconds per day – was subtracted, it was found that the actual error was only five seconds slow relative to the known longitude of the port of Kingston.

So in terms of testing standards, COSC and the Laboratoire de Précision are identical; in terms of testing procedures, however, there’s a big difference. I don’t know whether or not, for general purposes, this is going to make any difference to consumers since METAS-controlled Master Chronometer certification is already almost universal across Omega’s entire catalog anyway. The press release from Swatch Group does hint, however, that the finer-grained data from the Laboratoire de Précision might be relevant to its standardization procedures for the Spirate system.

“For OMEGA, the arrival of the Laboratoire de Précision represents a great leap forward in precision standards. For example, the recent milestone precision of its Spirate™ System not only delivers outstanding technology in watchmaking, but it also demands the latest technology in measuring systems. With access to extensive data and crucial technical details, OMEGA will now be able to analyse and improve its calibres for the future and refine the small margins that can determine the reputation of a watchmaker.” So far, the Spirate system, which is a fine regulation mechanism allowing adjustments in increments of 0.1 seconds per day, has only been introduced in one model; the system adds parts and complexity to the oscillator system but I’m sure Omega has already run the numbers on economies of scale if the system’s rolled out across its entire product lineup, as it did for Master Chronometer certification and for that matter, for the co-axial escapement.

There’s a marketing and political dimension to this as well, of course; Omega continues to look for points of differentiation between it and its non-SG competitors (including, obviously, Tudor) and who knows if there was anything more than that to Omega’s decision to end its relationship with COSC – differentiating itself from its competitors might have been all the justification it needed. Higher precision in metrology may indeed result in better chronometry – certainly this has been the case for most of the history of watch and clockmaking. For now, the pipeline for standards at Omega and Tudor is still ISO 3159 certification to Master Chronometer certification, but if as Omega hints, the higher precision measurements at the Laboratoire de Précision might eventually lead to an internal standard better than Master Chronometer … well, that would up the ante.