In many cases, class certification is the most critical step in a putative class action. Statistical and econometric modeling are key to supporting or defeating class certification in many cases - by evaluating a pattern or practice in employment discrimination cases, a design or defect in product liability cases, or assessing whether class-wide relief is appropriate in antitrust cases. Aegis experts provide rigorous statistical analysis of putative class data and we present methodology and findings in intuitive and jargon-free language that speak directly to the critical issues in class certification.