The "English Language Development among American Indian English Learner Students in New Mexico" study examined ways to better understand progress toward English proficiency among American Indian English learner students. The study examined two statewide cohorts of American Indian students identified as English learner students at initial kindergarten entry in 2013/14 or 2014/15 in New Mexico public schools. The study found that most American Indian English learner students were not reclassified as English proficient within five years. Similarly, most American Indian English learner students did not meet grade-level standards on New Mexico state assessments in English language arts and math in grades 3 and 4, regardless of whether they attained English proficiency and were reclassified within five years. The results of this study can be used to determine how best to support English language development among American Indian English learner students. This document presents the following two appendixes that accompany the study: (1) Data and methods; and (2) Supporting analyses. [For the full report, see ED618962. For the Study Snapshot, see ED618963.]