Functional correlations between the efficiency indicators of investments

In the methodology for evaluating the validity of investments (without portfolio investments), recommended by the World Bank, three methods are usually used: payback period, net present value and internal rate of return. Functional correlation can be set up between these indicators and this paper presents an interdependence research, based on the five projects form of different industrial branches.   Key words: Investments, efficiency, net present value, payback period, internal rate of return.