The quantitative study was a comparison of Limited English Proficient (LEP) students' assessment outcomes when taught by a teacher with specialized training and when taught by teachers with no specialized training. The comparison of 2007-2008 Northern Nevada LEP third grade student scores in the content areas of English language arts and mathematics assessments were analyzed to determine the effectiveness of a Teaching English as a Second Language certification. The analysis was focused on two types of student outcome scores: total LEP mean scores and LEP proficiency levels. The descriptive analysis of the 1,320 LEP students' average mean scores was higher in English language arts and mathematics when students were taught by a TESL certified teacher. The independent t tests for LEP students' "proficiency level" scores in English language arts and mathematics yielded no statistically significant results and failed to reject the null hypotheses. [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.]