Inter-rater agreement refers to the level of consistency or agreement between different raters or observers when they assess the same phenomenon. It is commonly used in research and clinical settings to ensure that measurements or evaluations are reliable. High inter-rater agreement indicates that different raters are likely to arrive at similar conclusions, while low agreement suggests variability in their assessments. To measure inter-rater agreement, various statistical methods can be employed, such as Cohen's Kappa or Fleiss' Kappa. These methods help quantify the degree of agreement beyond what would be expected by chance. Ensuring good inter-rater agreement is crucial for the validity of studies in fields like psychology, medicine, and education.