The study emphasises the joint importance of investment and efficiency of investment (indicated by its rate of return) for economic growth. In particular the role of public investment is analysed. It is shown that the differing quality of investment has played a significant role in the different economic growth experiences of the EU, Japan and the US. It is argued that to increase growth in the EU it may not be necessary to increase the investment rate. Long-term growth could also be restored by a sufficiently strong increase of the efficiency of investment.