This cross-sectional, correlational, explanatory study aimed to explain the influence of administrator/student ratios on the percentage of teachers that receive effective or highly effective ratings on their summative evaluations scored by the administrators at those schools. Other school and student variables were included with administrator/student ratios as controls. The aim was to be the seminal study that provides research on factors (school and student) outside of the teacher evaluation process that influence the ratings teachers receive. Poverty and per-pupil expenditures influence teacher summative evaluation scores with regression models having R squared values of 6.3% and 6.2%. Administrator/student ratios do not influence teacher summative evaluations scored by the administrators at their schools. However, the data did provide a rationale for recommending future research on the topic. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]