The migrant lifestyle, in which a student moves to a new school nearly three times per year, destroys the continuity of educational programs and contributes to abnormally high dropout rates. Educational testing can help improve educational continuity for migrant students by yielding valuable information about their levels of skills mastery so they can be placed at appropriate instructional levels. Three types of educational tests are in use: norm-referenced tests, criterion-referenced tests, and locator tests. Although often misused to measure short term academic gains, locator tests can quickly place migrant children within three months of their work level. One locator test, the Zip Test, is designed specifically for migrant students. It uses familiar experiences to allow individual assessment of English language facility and rapid and reasonably accurate placement of children aged 5 to 12 in math and reading. Test bias and research problems make many tests inappropriate for minority migrant children. Conducting the longitudinal research necessary to establish a test's validity and reliability for migrant students is extremely difficult because of the students' high mobility. (NEC)