Abstract: Efficiency interval length might be too long to evaluate the effectiveness of decision-making units well if range of input and output variables interval is large. Divides input and output interval into sub-intervals,and calculates efficiency of decision-making units in different sub-intervals respectively,furthermore,comprehensive efficiency intervals are solved to use as standards of effectiveness evaluation. Length of comprehensive efficiency intervals is shorter than that in the results of classical algorithms,which is easy to be used to compare efficiency of investment projects as applying to evaluate the investment projects.

Key words: data envelopment analysis with interval number, efficiency interval, investment projects, Efficiency evaluation