Improved parabolic trough concentrating collectors will result from better design, improved fabrication techniques, and the development and use of improved materials. This paper presents and implements an easily applied methodology that quantifies the performance potential of selected parabolic through component improvements from a systems viewpoint and uses performance data to determine the economic value of each improvement. Specifically considered are evacuated receivers, silvered glass reflectors, improved receiver selective coatings, higher optical accuracy concentrators, and higher transmittance receiver glazings. Upper-bound costs for each improvement are provided as are estimates of the increased solar energy system rates of return made possible by these improvements. The performance and economic potentials of some of these improvements are substantial, especially at higher collector operating temperatures.