Andreas Wyss, CEO of the COSC, on the Need to Adapt and a “Super-COSC” Certification to Come

If you own mechanical Swiss watches, one of them potentially came to you with a COSC chronometer certificate. But not everyone knows exactly what this certificate means. The COSC is the Contrôle Officiel Suisse des Chronomètres or the Official Swiss Chronometer Testing Institute. COSC certifies Swiss-made movements or watches as chronometers (not to be confused with a chronograph) if they meet specific precision standards. To achieve this, they need to pass a series of tests over 15 days, in five different positions and at three different temperatures. In the vast majority of cases, the tests are performed on movement before casing. Among different criteria, the precision must not vary by more than -4/+6 seconds per day. If the number of certificates delivered by the COSC has been growing regularly, the association faces several challenges. Besides the need to be better known, it needs to evolve in view of the emergence of numerous new quality labels (Master Chronometer, Superlative Chronometer, Geneva Observatory, Laboratoire de Précision). Andreas Wyss, CEO of the COSC, explains to MONOCHROME how they plan to adapt.

Xavier Markl, MONOCHROME – Andreas, thanks for having us. How and why was COSC created?

Andreas Wyss, CEO of COSC – The COSC (Contrôle Officiel Suisse des Chronomètres) was founded in 1973 through a shared initiative by Swiss watch brands, the Fédération Horlogère, and public authorities, with the goal of standardising precision measurement across the industry.

Prior to the COSC’s creation, brands obtained certificates from various independent “Bureaux d’Observation” (observation offices) located in different Swiss cantons – Bern, Neuchâtel, Solothurn, Geneva, and Vaud. Each of these offices operated under its own procedures and standards, which posed challenges, particularly for watchmakers with production facilities in multiple regions. This fragmented system also created confusion for clients trying to understand the meaning of chronometric certification.

The solution was the formation of a unified, centralised organisation, the COSC, the Official Swiss Chronometer Testing Institute. Political authorities and the association placed several conditions on its creation:

• The existing observation offices and their staff were to remain in their respective cantons
• The association was to remain majority publicly owned
• The staff were required to work exclusively for COSC

As a result, the COSC General Assembly today consists of 19 delegates, 10 of whom represent the public sector, ensuring continued public oversight. Currently, COSC operates three laboratories in Le Locle, Saint-Imier, and Biel.

So, what does a COSC Certificate encompass?

What few people know is that we have 4 certifications. The best known is for wristwatches, based on the ISO 3159 norm. Another one is for pocket watches, for which there is no international norm, so we created one. There is one for clocks. And last but not least, there’s one for quartz watches.

The best known of all 4, relying on the ISO 3159 norm, is based on 7 criteria. In particular, the average rate must remain within -4/+6 seconds per day over the course of the 15-day testing procedure. Besides this, the tests also include thermal variance, position testing or power reserve variance.

Are we talking about watches or movements?

We certify both complete watches and movements, although the majority of the certificates we issue are for movements. This is primarily due to the logistical and production challenges brands face when submitting fully assembled watches.

Today, we face two main criticisms: the current standard dates back to 1976 and has seen very little evolution since. We primarily certify movements, raising the question: What happens after the movement is certified?

How, then, can COSC evolve to address these criticisms?

First and foremost, although the standard has not evolved significantly since 1976, obtaining a COSC certificate is still far from easy. The volume of movements submitted has grown substantially over the years, and maintaining consistent quality at scale is a real challenge. Yet, the failure rate has remained relatively stable, between 3% and 5%, despite these rising volumes. This demonstrates that watchmakers are mastering quality control more effectively than ever.

Our ambition is to deliver certification not only to brands and watchmakers, but also to clients. When someone purchases an exceptional timepiece, they should have the assurance that it has been tested and validated by a truly independent and neutral authority. This is fundamentally different from any form of internal certification.

We also believe it’s time to go beyond precision alone. While ISO 3159 may be viewed as outdated in some respects, it remains the only internationally recognised standard for chronometer certification. For that reason, we will continue to use it. And again, achieving COSC certification is no trivial matter.

But of course, we’ve observed the evolution of other certification models – such as Rolex’s Superlative Chronometer and Omega’ and Tudor’s Master Chronometer. In the same spirit, we intend to take things further ourselves. For brands that are interested, we will offer options beyond the current COSC certification, while continuing to uphold the ISO 3159 standard. Some type of “Super COSC” certification, if you wish. We’ll communicate about this in the coming months. 

The goal is to certify not just movements, but complete watches. The criteria for precision will be updated to reflect the realities of modern watchmaking, but the scope will go far beyond precision alone. Our ambition is to promote Swiss excellence as a whole. This could include aspects such as water resistance, magnetic field resistance, power reserve, and more. In short, we aim to go well beyond what we currently offer. 

For more information, please visit www.cosc.swiss.