In VAN GENT [2004] graphs were presented in which the datasets of VAN DER MEER [1988] and VAN GENT ET AL. [2003] were compared, but in this comparison a number of parameters were not correctly transformed into a comparable format. In this M.Sc. thesis after an extensive analysis to the datasets all parameters of the datasets of Van der Meer were transformed into the same format as the parameters used by Van Gent. In the same way the dataset of THOMPSON & SHUTTLER [1975], which formed the basis of the work of Van der Meer, was treated. The inclusion of correction factors for the effects of stone roundness from LATHAM ET AL. [1988] gave remarkable effects on a certain part of the dataset of Van der Meer which showed more damage than average. After this still differences could be seen between the datasets of Van der Meer and Van Gent. Using the statistical T-test these differences are approved. Explanations for the differences found between the datasets of Van der Meer and Van Gent can be found in the fact that most of the tests of Van Gent. were done with shallow foreshores where Van der Meer did most tests with deep water conditions. Tests by a number of M.Sc. students at Delft University of Technology showed that tests with identical spectra, but with different foreshore slope angles show different damage patterns. In the dataset of Van Gent also the 1:30 foreshore slopes on average show more damage than the 1:100 slopes. In further research the influence of the foreshore should be incorporated in the stability formulae by a foreshore Iribarren parameter. Also a detailed investigation to the effects of wave breaking on shallow foreshores is needed. For this the complete dataset of Van Gent needs to be available and accessible.