The paper analyzes the VAIC (Value Added Intellectual Coefficient) and the subsequent developments 20 years after the first formulation made by Ante Pulic. The paper deeply analyzes the concept and proposes future directions for research and applications of the methodology. Three main directions for research are described: (i) value creation for stakeholders and investment in human capital; (ii) sustainability of knowledge-based strategies from an economic and social point of view; (iii) a framework for continuous increase of knowledge work productivity. Two real applications of calculation of the Knowledge Work Productivity are described.