This teacher guide is meant to provide a rationale for an assessment model for Spanish writing. A wide variety of bilingual and English-as-a-Second-Language (ESL) programs have emerged to meet this challenge, and writing is integral to these approaches because learning to write well in Spanish is often the key to academic success in English. Changing demographics, the history of bilingual education in the United States, and the research that supports instruction in native language all point to the importance of a new Spanish model. The guide also includes the characteristics of effective Spanish writing, rubrics for scoring student performance based on these characteristics, and student writing samples--all from the work of bilingual and ESL teachers in the field. Also included are classroom applications and strategies for teaching Spanish writing. There are three appendices: "Scoring Guides for Sample Papers"; "Project Methodology"; and "Bibliography" and four tables: "Growth of Total U.S. Student Enrollment and LEP Enrollment"; Growth of Total Northwest Student Enrollment and LEP Enrollment"; "Number and Percentage of Northwest LEP Students Who Speak Spanish"; and "Possible Sources of Bias and Distortion in Student Assessments." Numerous figures, diagrams, illustrations, and 130 print and Web references are included. (KFT)