Analysis of the Annals of Joseon Dynasty: Careers of bureaucrats, system of governance, and stability

Can one characterize the long-term modus operandi of a complex historical social system that has lasted several centuries? The primary obstacle would be the availability of data with sufficient richness and scale collected using a consistent methodology. Even if a system of an official, authoritative, and consistent record keeping had existed during the historical regime's existence, a complete preservation of the records after many centuries of historical turbulences, either man-made or natural, up until the present day would be exceptionally challenging. If such data were to survive, however, recent rapid developments in our ability in data archival, retrieval, and statistical analysis could open up new avenues for understanding the workings of those historical social systems, enabling us to gain fresh perspectives on long-standing questions of how they evolved and how they ultimately ceased to exist. The historical Korean kingdom of Joseon is a rare such case, having maintained a consistent record-keeping system throughout its five-centuries of existence. Since its bureaucratic administration was the primary mechanism through which the dynasty maintained its remarkable stability, we analyze the career trajectories of its officials using two comprehensive government records: The Annals of the Joseon Dynasty that details the kingdom's affairs, and the Bangmok that contains the personnel information on the bureaucrats who passed the civil service examination, the fundamental gateway into a career in governance. Our primary finding from the analysis of the career trajectories of 14638 bureaucrats is that Joseon's system maintained a stable behavioral pattern for four centuries represented by a characteristic Gini coefficient of 0.52 of Total Success Index (TSI) of the bureaucrats, then the stability disappeared in the 19th century as it rapidly increased to 0.78, signifying a significantly elevated level of inequality. We also find that it coincided with a 2.02-fold increase in the representation of powerful clans (Sedoga) within Joseon's bureaucracy. These findings provide a quantitative indication of the systemic corruption in Joseon's long-lasting meritocratic system that preceded the dynasty's demise shortly after.