FAIR is an analytical risk model, whereas most information security risk methodologies in use today are Capability Maturity Models (CMM) or checklists. Analytic models attempt to describe how a problem-space works by identifying the key elements that make up the environment and the relationships between those elements — e.g., Newton’s laws of the physical world described how things like gravity work. If the models are relatively accurate (no models are perfect), then analyses performed using the models should consistently align with our experience and observations. With those elements identified, measurements can be made that enable risk quantification and performance of what-if analyses, neither of which can be performed with checklist or CMM analyses.
The other methodologies answer different questions:
FAIR provides the means to answer questions like:
Note that all three methodology types can be useful for most organizations, and should be complementary.