Research into hearing loss has expanded significantly in recent decades, providing valuable insights into its epidemiology, causes, and psychosocial impacts. However, the strength and applicability of this body of evidence is shaped—and sometimes constrained—by a range of methodological limitations that recur across systematic reviews, meta-analyses, and primary studies. This chapter systematically outlines the most common limitations identified in the reviewed literature, including design flaws, biases, measurement inconsistencies, and analytical gaps. By critically examining these issues, it aims to provide researchers, clinicians, and policy-makers with a clearer understanding of where current evidence may fall short and how future work can be refined to strengthen the empirical foundation of hearing loss research.