“…(i) by geographical area, most studies (20) were carried out in North America (19 exclusively in the United States and one for learners in the United States and Canada); followed by Europe (5 studies: 3 in Spain and 2 in the United Kingdom); Asia (4 studies, specifically in Taiwan, Singapore, China and Japan); and finally, Australia (2 studies) and Africa (2, one in South Africa and the second in Nigeria). (ii) according to the level of education, university and post-university learners at any stage were the most frequent research populations in our sample (in 28 of the 33 studies considered), compared to lower levels of education (in the 5 remaining studies, specifically Agbatogun, 2012;Barnes, 2008;DeSorbo et al, 2013;Mun, Hew, & Cheung, 2009;and Vital, 2012). (iii) by field of education, as previously commented, we used the codification of our selected studies according to a classification of disciplines into 2 dimensions and 4 categories inspired by the well-known Becher (1989) Following this classification our sample, grouped by discipline, is relatively balanced, with 9 studies in the pure soft category; 8 in applied hard; 6 in pure hard, and 5 in applied soft.…”