Knowledge Intensive Business Services (KIBS) are intermediary firms which specialise in knowledge screening, assessment and evaluation, and trade professional consultancy services. The remarkable rise of this broad class of activities is perceived by many as the natural by-product of modern knowledge economies within which increasing specialisation induces the need for professional agents in the markets for external knowledge. This paper addresses critically a conceptual flaw in the specialised literature

which portrays KIBS as a homogeneous group of activities. Using official data on occupational information in the United States we observe and analyse high variety across KIBS sectors? occupational structures and skill requirements.