The enforcement of competition law suffers from the lack of adequate tools to study the markets in which innovation and, more generally, economic change are the main drivers of competition. In such cases, the traditional (microeconomic) analytical framework, based as it is on the trade-off between static and dynamic efficiency, is only able to provide unsatisfactory answers, affected by structural discretionality. This inadequate outcome originates from the fact that the underlying theory is not fit for practical implementation. The article aims at providing a description of the fundamental features of change-based competition - and of its efficiency in terms of dynamic social welfare - as derived from the mainstream literature on management science. This framework is then used to develop some general principles for the enforcement of competition rules.