Modern health-care is a complex socio-technical system, and as such variability is normal and necessary. The ability of a complex system such as health-care to quickly and correctly adapt to varying circumstances is crucial to how well the system works. Both increased compliance to guidelines, and a concurrent ability in individuals to deviate from these guidelines in certain situations, can be expected to increase safety. Today, we know too little about these adaptations, and how they affect safety. New knowledge is needed to describe and understand complexity and variability in health-care. FRAM (Functional Resonance Analysis Method) is one such method.