Supplement 1. Selection of items from the EU Kids online, Global Kids Online and Livingstone et al. (2017) versions on the online parental mediation dimensions of each questionnaire.

The only evaluation instrument used is the integrated and paired questionnaire for the evaluation of parental mediation strategies for children and families/guardians. This has been carried out by jointly analysing items from the available and recent versions of the EU Kids Online project (http://www.eukidsonline.net/) in its 2017 version (for children), Global Kids Online (http://globalkidsonline.net/) (children and legal guardians version) and from the work of Livingstone et al. 2017 (where only legal guardians are assessed). The construction process can be found in Annex/Supplement A/1. Although the items are very similar in each of the versions, there are some differences, both in the number of items that make up each dimension and in the response scales. The guiding principle has been to make a proposal of maximums that combines all the possible items of the three versions, with the exception of item 18 of restrictive mediation, which has not been included in the statistical analyses as it has a different response scale to the rest of the items of the dimension (See supplement 1). Thus, all items have been added to this version and paired for the child and family/guardian formulas

本研究采用的唯一评估工具为整合式配对问卷，用于评估面向儿童与家庭/监护人的家长媒介使用调解策略。该问卷通过整合分析以下现有最新版本问卷的条目编制而成：欧盟儿童在线项目（EU Kids Online，http://www.eukidsonline.net/）2017年版（面向儿童）、全球儿童在线项目（Global Kids Online，http://globalkidsonline.net/）（面向儿童与法定监护人版），以及利文斯通等人（Livingstone et al.）2017年的研究成果（仅针对法定监护人）。该问卷的编制流程详见附录/补充材料A/1。尽管上述三个来源的问卷条目相似度较高，但各维度所包含的条目数量以及作答量表均存在一定差异。本问卷的编制原则为尽可能整合三个版本的全部可行条目，但限制性调解策略维度的第18题除外——由于该题的作答量表与该维度其余条目不一致，故未将其纳入统计分析（详见补充材料1）。因此，本版本整合了全部符合要求的条目，并针对儿童与家庭/监护人两套问卷进行了配对设计。