A method for the evaluative analysis of a photovoltaic layer system is described. The method applies to a semiconductor layer forming a pn junction: an electric current is generated in the layer system; a spatially resolved thermal image of the surface of the layer system is generated; an intensity distribution of the thermal radiation relative to the respective number of pixels with the same intensity value is determined; an intensity mean/median from the intensity distribution is determined; an intensity interval based on a specifiable measure for a scattering of the intensity distribution is determined; a characteristic number is determined; and the characteristic number or a calculation value based thereon is compared with a specifiable reference characteristic number.