2.7. Quality Appraisal

The quality assessment was conducted with the studies included in this systematic review. This evaluation was developed by two authors, with the third author mediating only in cases of disagreement. For this purpose, a template to help understand a qualitative study designed by the Critical Appraisal Skills Programme Español (CASPe) [20] was used. This tool is composed of 10 questions, which are intended to help assess the quality of qualitative studies. These questions have three answer options: “YES”, “NO”, and “NOT SURE” [20].

To rate the quality levels of the studies included, we used the classification suggested by Butler et al. [21]. This categorization scores the “YES” response with 1 points, the “NOT SURE” with 0.5, and the “NO” with 0. Subsequently, these authors classified these scores into four categories: scores of high-quality (9–10), scores of moderate-quality (7.5–9), scores of low-quality (less than 7.5), excluding those studies with less than 6 points [21]. However, in our review, only the first three categories have been used, including in the low-quality category all those studies scoring below 7.5 points and no studies have been excluded based on their quality.

In addition, and with the objective of performing some kind of sensitivity analysis [22], a study of the relative contribution of the studies according to their quality has been performed, considering a process previously suggested by other authors [19]. Thus, this review has considered the information provided by the different studies to the results of our review as a relative contribution. Therefore, when a study is scored with a relative contribution, for example, of 5, it means that this study has provided information to the results on 5 occasions.