A model for quantitative analysis of core-level x-ray photoemission spectra based on relative core-level intensities for different elements is proposed. The model, which is generally applicable to single crystalline materials, allows an indirect comparison between electronic and structural properties of a solid material. In particular, for the highly anisotropic high-temperature superconductors, much information can be extracted using the proposed scheme. The model is exemplified for the ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$ system, the experimental data from which show an excellent agreement with the theoretical predictions, thus validating the outlined approach. The results confirm that cleaved crystals of ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$ are terminated by the Bi-O layer.