The intact rock strength of a rock mass has been determined by several different means in the context of research for slope stability assessment. The intact rock strength was determined with unconfined compressive strength testing, Schmidt hammer, Equotip, and estimation by so-called ‘simple means’. Estimation by ‘simple means’ denotes estimating the intact rock strength by hammer blows, crumbling by hand, etc. Many different people to avoid observer bias have done hundreds of assessments of intact rock strength by different means on the same rock masses. The results show that in many cases an estimation of intact rock strength by ‘simple means’ is more representative for establishing the intact rock strength of a rock mass than establishing the intact rock strength by more elaborate testing.