Conduct comprehensive research for assigned appeals and grievances, including review of enrollment and eligibility, provider participation status, benefit plan provisions, authorization records, claim history, clinical or administrative documentation, prior correspondence, and the circumstances surrounding the denial of services or rejection of claims. Assess each submission to confirm that it meets applicable appeal or grievance criteria, identify the appropriate case type, category, subcategory, level of review, and root cause, and document the classification accurately in designated systems.