We analyze the filing-side legal infrastructure of eviction using 755,004 Philadelphia Municipal Court landlord-tenant records filed between 1969 and 2022, of which 747,125 are residential. Eviction in Philadelphia is organized upstream by a concentrated plaintiff-side bar, durable plaintiff-attorney dependence, repeated use of the same properties, and recurring tenant-name exposure. Between 1983 and 2022, the ten most active plaintiff attorneys handled 82.2% of represented plaintiff-side cases per year on average, compared with 14.8% for the ten most active plaintiffs. Large plaintiffs depend heavily on a single attorney: among plaintiffs filing at least 101 cases, 78.3% of each plaintiff's filings are handled by that plaintiff's most-used attorney, on average. Repetition is likewise central to the docket. Across the residential filing universe, 48.8% of cases occur at addresses with a prior filing in the preceding year, and 23.6% at addresses with six or more prior filings; these repeats are usually filed by the same plaintiff and follow a more default-heavy, less agreement-heavy pathway. We further examine a narrower mechanism: strict switches into specialist plaintiff-side counsel, defined as a plaintiff changing attorney to one in the prior-year top ten. Filing counts rise around the switch with non-flat pre-trends, indicating organizational reconfiguration rather than a clean exogenous shock. Within-plaintiff and within-plaintiff-property comparisons yield more stable estimates: judgment by agreement, fee share, waiver language, and corrected lockout-trigger language decline, while deadline language rises. We interpret eviction as a layered upstream process in which concentrated counsel, repeated places, and recurring tenants produce filings before any courtroom bargaining or adjudication occurs.

翻译：我们利用1969年至2022年间费城市政法院提交的755,004份房东-租户记录（其中747,125份涉及住宅）分析了驱逐案中提起诉讼一方的法律基础设施。费城的驱逐案在上游由集中的原告律师队伍、持久的原告-律师依赖关系、同一房产的反复使用以及租户姓名的重复出现所组织。1983年至2022年间，最活跃的十位原告律师平均每年处理了82.2%的有代理律师的原告方案件，而最活跃的十位原告仅处理了14.8%。大型原告高度依赖单一律师：在提交至少101起案件的原告中，平均每位原告78.3%的案件由其最常用的律师处理。重复性同样是案件清单的核心。在整个住宅案件提交范围内，48.8%的案件发生在前一年已有案件提交的地址，23.6%发生在有六起或更多先前提交的地址；这些重复案件通常由同一原告提交，并遵循更偏向缺席判决、更少达成协议的模式。我们进一步考察了一种更具体的机制：严格转向专业原告方律师，定义为原告更换律师至前一年排名前十的律师。诉讼提交数量在更换前后呈非平坦的前期趋势上升，表明这是组织重构而非干净的外生冲击。在同一原告和同一原告-房产的比较中，估计结果更为稳定：通过协议判决、费用分担、弃权语言和修正的驱逐触发语言减少，而截止日期语言增加。我们将驱逐解释为一个分层上游过程，在此过程中，集中的律师、重复的地点和重复出现的租户在任何法庭谈判或裁决发生前就产生了诉讼提交。