“…Third, some measures of HL were used in an inconsistent manner across studies, making comparisons of the findings difficult. For example, the original four categories of the REALM (i.e., 0-3 rd grade, 4 th -6 th grade, 7 th -8 th grade, 9 th grade and above) were used in some studies [22,33,34,35,36,37], but were reduced to three [38,39,40,41] or two [14,15,42,43,44,45,46,47] in others -with some loss of information and thus implications for the validity of the findings. In two studies, the REALM was treated as a continuous variable [16,48].…”