A Most Endangered list is a common programmatic tool used by historic preservation advocacy groups. These lists allow the organizations to focus their support on a small, representative selection of threatened historic resources. While these programs are widely accepted and implemented, there has been no formal investigation into their use or study of the subtle differences that make each program unique. This thesis analyzes statewide Most Endangered programs with the goal of determining if there are variables that can enhance the program’s effectiveness at accomplishing the organization’s goals. Organizations that wish to examine the usability or effectiveness of their Most Endangered programs do not have easy access to the information that is needed for an objective analysis. This is the current situation at Preservation Texas, Texas’ statewide preservation advocacy organization. The staff there is currently evaluating the organization’s Most Endangered program, making this document a timely and useful tool for their use. This thesis seeks to provide a base from which Preservation Texas, or any preservation advocacy organization, can begin to examine their own program’s operations. For this project I performed research on statewide Most Endangered programs at both macro and micro levels. An initial investigation of the web-presence of these programs enabled me to make broad determinations about their operations. I then selected five of these organizations for a closer study. Through interviews and additional research, it was possible for me to begin to compare and contrast the programs while analyzing their differences from an impartial perspective. Through this careful study, I developed a list of eight criteria that are indicative of an effective Most Endangered program. In the final chapter I use these eight criteria to analyze Most Endangered programs, specifically the one operated by Preservation Texas. By applying my research and observations, I am able to reach constructive conclusions about the operations and functions of Preservation Texas’ Most Endangered program. While this thesis was written for the benefit of a specific organization, the findings are applicable to any organization that has, or is thinking about starting, a Most Endangered list. / text