The aim of the interlaboratory REAL-80 exercise, organized by the International Atomic Energy Agency, was to determine the state of the art in 1981 of the capabilities of laboratories to adjust neutron spectrum information on the basis of a set of experimental activation rates, and to subsequently predict the number of displacements in steel, together with its uncertainty. The input information distributed to participating laboratories comprised values, variances, and covariances for a set of input fluence rates, for a set of activation and damage cross-section data, and for a set of experimentally measured reaction rates. The exercise dealt with two clearly different spectra: the thermal Oak Ridge Research Reactor (ORR) spectrum and the fast YAYOI spectrum. Out of 30 laboratories asked to participate, 13 laboratories contributed 33 solutions for ORR and 35 solutions for YAYOI. The spectral shapes of the solution spectra showed considerable spread, both for the ORR and YAYOI spectra. When the series of predicted activation rates in nickel and the predicted displacement rates in steel derived for all solutions is considered, one cannot observe significant differences due to the adjustment algorithm used. The largest deviations seem to be due to effects related to group structure and/or changes in the input data. When comparing the predicted activation rate in nickel with its available measured value, we observe that the predicted value (averaged over all solutions) is lower than the measured value.