Many national reports indicate that more attention needs to be placed on writing and the teaching of writing in schools. The purpose of this quantitative study was to, first, examine the structure of the DWA and, second, to use the scores from the DWA to examine the relationship between ELL status and writing proficiency. Five major research questions were addressed: (1) Does the DWA provide valid and reliable scores of writing proficiency for students in general and for specific groups of students based on ELL status and ethnicity? (2) What is the relation between ELL status and writing proficiency for ninth-grade students attending public schools in Utah during the years 2004, 2005, 2006, and 2007, and to what extent do student variables, such as gender, social economic status, and ethnicity, independently and cumulatively explain the relationship? (3) To what extent do the school variables, percent of low-income students in a school, percent of minority students in a school, size of the school, and mean ELL status at a school independently and cumulatively explain the relation between ELL status and writing proficiency? (4) To what extent do the district variables, percent low-income students in a district, percent minority students in a district, size of the district, mean ELL status in a district, and whether a district is urban or rural independently and cumulatively explain the relation between ELL status and writing proficiency? (5) To what extent does the relationship between ELL status and writing proficiency interact with ethnicity? The results of the study indicated that the DWA was a valid and reliable form of writing assessment. Determined also was the fact that deficiencies in writing skills are at their greatest when ethnicity, social economic status, and limited English language proficiency are considered. The results of the present study have suggested ways to rethink how writing is conceptualized and assessed, how past instructional practices have possibly resulted in disparities among ethnic groups, how writing skills vary with student, school, and district characteristics, and how differential writing instruction may benefit students of different ethnic groups and ELL statuses. A "one-size-fits-all" approach to writing instruction will not benefit all students in Utah or throughout the nation. Because writing differs between ethnic groups, writing instruction must differ as well. [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.]