The testing of English language learners (ELLs) is, to a large extent, a random process because of poor implementation and factors that are uncertain or beyond control. Yet current testing practices and policies appear to be based on deterministic views of language and linguistic groups and erroneous assumptions about the capacity of assessment…

We contend that generalizability (G) theory allows the design of psychometric approaches to testing English-language learners (ELLs) that are consistent with current thinking in linguistics. We used G theory to estimate the amount of measurement error due to code (language or dialect). Fourth- and fifth-grade ELLs, native speakers of…