Certificate. Language teaching certification courses such as the Royal Society for the Arts TEFL Certificate are not uncommon for expatriate language teachers. These courses usually provide an orientation to practical teaching methodology for in-service teachers of English. While the range of the curriculum is certainly much broader than the typical in-house training scheme, the certification courses focus mostly on practical classroom management techniques, correction or feedback methods, syllabus organization principles and assessment techniques. Instructors with this kind of training were encoded with 'CRT' in the meta-analysis. Master degree (MA). Instructors in language schools and company language training departments holding masters degrees in any field are still relatively rare. In the context of the present study, any master degree achieved was coded as 'M.A.'. The possible ambiguity in encoding a bachelor degree in any field as a single label also applies to the coding of master's degrees. Some bachelor degrees, for instance, may be in a modern language or linguistics, while some master degrees may in fact be in diverse fields ranging from finance to geography. The specific details of graduate training in a particular field were, unfortunately, not available from company or language school program administrators, thus making for potential inferential problems in observing differences in effect sizes
attributable to educational qualifications.