Evidence syntheses in educational technology research: What is not published in English is not visible? A tertiary mapping review

Evidence syntheses, such as systematic reviews, aimto summarise the current state of research in a field,often using the publication language of a study as acriterion for inclusion or exclusion. However, this hasserious implications for capturing evidence from awider range of geographical areas, and the potentialfor linguistic bias. In order to explore this issue, atrilingual tertiary mapping review of 446 evidencesyntheses within the field of educational technology(EdTech) and published in English, Spanish andGerman was undertaken, analysing the frequencyof multi- and monolingual evidence syntheses,reasons for language choice by research teams,and the composition of research teams in multi-and monolingual evidence syntheses. Items wereincluded if they were a form of evidence synthesiswith an explicit method section, indexed within ERIC,Scopus, Web of Science, Dialnet, FIS- Bildung, orGoogle Scholar, education-related, and publishedbetween 1983 and May 2022. The results showed thatonly eight languages were considered in publishedsyntheses, only five languages were used to constructsearch strings, most evidence syntheses includedresearch published in English without explaining why,and multilingual research team composition did notpredict multilingual evidence syntheses. The findingssuggest the need to address publication languagesnot only as a formal criterion but as an integral aspect of methodological approach, influencing the contentand scope of syntheses in educational research.