Sibling Bonds as Protective Factors in Childhood Adversity: A Protocol for a Meta-Analysis of the Moderating Effect of Sibling Relationship Quality

Children who experience adversities early in life are at heightened risk for both immediate and long-term psychological challenges. Adverse experiences are widespread and are consistently associated with increased risks of physical and psychological difficulties. Resilience, the ability of individuals and systems to adapt successfully to adversity, must be considered across multiple levels, including individual, family, and community contexts. One potential resilience factor is sibling relationships. Warm and supportive sibling bonds provide a sense of security, promote socioemotional development, and are linked to better psychological adjustment, potentially mitigating the negative effects of early adversity. Given the widespread prevalence of adversity, as well as their profound impact on individual well-being, it is essential to identify protective and mitigating factors that can buffer against negative outcomes. One such potential factor is sibling relationship quality, which may play a moderating role in how children cope with adversity. This meta-analysis aims to synthesize existing research to evaluate the extent to which positive sibling relationships mitigate the effects of adverse or stressful experiences on child outcomes. Specifically, the following research questions will be addressed: 1. To what extent does sibling relationship quality moderate the effects of adversity on child outcomes? 2. How do sibling characteristics (e.g., age gap, birth order, gender) and the type of adverse exposure influence the moderating role of sibling relationship quality?