Radiation damage in materials is a space and time multi-scale process, ranging from the atomic scale up to the macroscopic scale, and from the femtosecond up to several years. The prediction of the long term evolution of materials subjected to radiative environments (in the nuclear or in the space industry, as well as in the field of microelectronics) therefore requires the combination of several simulation and experimental techniques able to cover the different space and time scales involved. X-ray diffraction (XRD) is highly sensitive to atomic displacements while probing macroscopic volumes of material. In this respect it is perfectly suited for the study of radiation damage. In this work it is shown how XRD can be quantitatively and qualitatively used in combination with numerical simulations, like molecular dynamics and rate-equation cluster dynamics, to analyze damage build-up in irradiated SiC and ZrC single crystals. Particular emphasis is laid on the methodological aspects of XRD data treatment in order to extract parameters such as damage-induced strain and disorder.