In-house programs (PRG). Some language programs provide training courses for their own
language teachers. These training courses typically provide neophyte teachers who are native speakers of English with strategies for using specified course materials or teaching
methods, usually devised on an in-house basis. The training regimen rarely includes an
outline of theories of cognitive development, language acquisition, or assessment, for their
chief purpose is to ensure some uniformity in the use of the materials sold as part of the
language training package. Programs providing in-house training for teachers were encoded
'PRG' in the meta-analysis.