Purpose – The purpose of this paper is to investigate the possibility to replace radio equipment compliance requirements based on equipment parameters with a set of simple metrics that accurately reflects spectrum utilization and spectrum-sharing efficiency. Design/methodology/approach – The approach taken is to go back to the basic factors that determine radio system behavior in a shared spectrum environment: radio frequency power, duty cycle and frequency occupation. By normalizing these parameters, device specificity is avoided and a statistical perspective on spectrum utilization and sharing becomes possible. Findings – The analysis shows that two technology-neutral metrics would be adequate to govern spectrum utilization and sharing: a spectrum utilization metric and a spectrum-sharing efficiency metric. These metrics form the core of regulatory requirements for shared frequency bands. Each shared frequency band could be assigned criteria based on these metrics that take into account the types of applications for which that band will be used. Research limitations/implications – This work is a first step that identifies the main factors that affect shared spectrum usage from a statistical point of view. More work is needed on the relationship between real-world interference and its abstraction in the spectrum-sharing rules. Practical implications – The metrics proposed could be considered as the basis for a new approach to the regulation of the license-exempt spectrum, and, by extension, as the basis for generic compliance criteria. Their use would facilitate the compliance assessment of software-defined radio technology. Social implications – This work has no direct social implications. Originality/value – This paper combines new work on spectrum utilization criteria with extensions of previous work on spectrum-sharing efficiency into a comprehensive proposal for a new approach to the regulation of the license-exempt spectrum.@en