This datafile contains the U.S. TIMSS 2003 data, including data that was collected only in the United States and not included on the international database available from the IEA, and a Data User's Guide. The additional data relate to the race and ethnicity of students and teachers, and the percentage of students in a school eligible for the Federal free and reduced lunch program. This datafile is intended to be used in conjunction with the international datafile available from the IEA.