The overall direction of this research is to improve the development of information systems within federal agency modernization efforts so that the systems produce a value to the federal agency that is significantly greater upon implementation than the investment required to develop the systems. Federal agencies are modernizing at an increasing rate and, before authorizing funds for each specific modernization investment, the Office of Management and Budget (OMB) requires agencies to show alignment to agency mission outcomes. OMB defines the Federal Enterprise Architecture Performance Reference Model (PRM) "Line of Sight" as a means to show this alignment. This research formulated the Line of Sight Evidential Reasoning Analysis (LSERA) method to provide a principled method for enterprise line of sight analysis that improves reasoning under uncertainty, the examination of evidentiary force, and the inquiry into results of contemplated alternatives. Evidentiary Reasoning theory and Multi-Entity Bayesian Network theory form the principled basis for LSERA. Given this basis, the LSERA method consists of the LSERA Argument model, and the LSERA Inference Model. The LSERA Argument Model is a structure for the development of an enterprise line of sight argument providing a facility to assist in the transformation of the enterprise line of sight into an evidential reasoning-based argument. Given the inherent uncertainty within the enterprise line of sight, the LSERA Inference Model supports analysts in reasoning about the likelihood of performance attainment in all areas of the enterprise line of sight. In LSERA, the analysts can adjust probabilities to externalize their subjective beliefs about relations as well as set causality levels, such as necessary or sufficient, among the enterprise line of sight relations. They can then examine the impacts of their beliefs on the likelihoods of performance attainment. In addition, the LSERA Inference Model also supports evidentiary force analysis, showing which pieces of evidence are forceful in asserting the likeliness of achieving performance, behavior and mission and customer results. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]