Neutron cross sections have been calculated for total dpa production, stable defect production at low temperature, and for free defect production at high temperature. Calculations using the NJOY cross section processing code and ENDF/B-V cross sections were used to obtain displacement cross sections for neutron-irradiated iron. Published models of Simons and Wied-ersich were used to obtain modified response functions for the production of stable defects at low temperature and for free defect survival, respectively. The effects of these different response functions on the energy ranges of significance in various neutron spectra and on the spectrum-averaged cross sections for these spectra have also been calculated.