The quantitative and qualitative data collected is combined into an overall Best Law Firms score for each firm. This data is then compared to other firms within the same metropolitan area and at the national level. Because firms are often separated by small differences in overall score, we use a tier system rather than ranking law firms sequentially. The first tier in each metropolitan area includes those firms that score within a certain percentage of the highest-scoring firms; the second tier, those firms that score within a certain percentage of the next highest-scoring firms, and so on. National rankings are based on metropolitan awards as well as on the number of offices each firm has and the level of legal activity in each jurisdiction. The number of tiers included in each practice area or metropolitan area ranking varies, and some specialties may not be ranked in metro areas in which there is not enough data to provide rankings in a particular specialty.