The federal Migrant Education Program provides supplemental instruction and support services to migrant children through grants to states under Title I, Part C, of the Elementary and Secondary Education Act. The reauthorization of Title I in 1994 contained new requirements that Title I schools help students meet new state standards developed for all children. Acting on that mandate, the Office of Migrant Education set goals for migrant student achievement based on high school completion rates, student performance on state assessments of reading and math, and school readiness of migrant children entering elementary school. This report examines the extent to which migrant students participate in state and local assessment and accountability programs and evaluates migrant student data collection methods and data quality. State and local migrant program directors and data and assessment records specialists were interviewed in California, Texas, Florida, Washington, Oregon, Kentucky, Kansas, Arizona, and Georgia. These states accounted for approximately 70 percent of migrant students in 1998-99. Findings focus on what assessment and accountability data are collected on migrant student achievement in the nine states, the states' ability to disaggregate migrant student data, testing accommodations related to limited English proficiency or student mobility, availability of data on migrant student graduation and dropout rates, other academic outcome data, accuracy and comprehensiveness of migrant student data, and current technological efforts to improve data quality and availability. Brief recommendations for improvement are offered. Extensive appendices present information on the nine states' assessment practices. (Contains 11 references, 8 tables, and 1 figure.)(SV)