The English Language Proficiency Assessments for California (ELPAC) is the successor to the California English Language Development Test (CELDT). Beginning in 2017–18, the ELPAC is the required state test for English language proficiency (ELP) that must be given to students whose primary language is a language other than English. The California Department of Education (CDE) expects to be fully transitioned from the CELDT to the ELPAC as the state's assessment of ELP by 2018–19.

State and federal law require that local educational agencies administer a state test of ELP to eligible students in kindergarten (or year one of a two-year kindergarten program, sometimes referred to as “transitional kindergarten”) through grade twelve (ages 3-21). The ELPAC is aligned with California’s 2012 English Language Development Standards , and is comprised of two separate ELP assessments:

1. Initial Assessment (IA)—an initial identification of students as English learners
2. Summative Assessment (SA)—an annual summative assessment to measure an English learner's progress in learning English and to identify the student's ELP level.

excerpt from https://www.elpac.org/about/