The optical efficiency of parabolic trough collectors depends on their geometric agreement with the parabolic profile design which, in turn, largely depends on the structure supporting the collector. A method for assessing the degree of agreement between the measured geometry and the theoretical design surface is described, which takes into account uncertainty in the point coordinates and is based on kernel smoothing and bootstrapping methods. The technique was applied to a 12 m long parabolic trough collector module with a newly designed supporting structure. The analysis revealed that there were significant differences between the estimated and theoretical surfaces in several parts of the collector.