Why were many premodern population counts inaccurate?

Premodern population counts were often inaccurate primarily because their objectives differed significantly from modern censuses. Rather than seeking to understand the structure of society, early inventories were typically designed to control individuals for specific state purposes, such as identifying people for taxation, military service, or forced labor.1

Because these counts were used to impose liabilities, it was rarely in an individual's interest to be accurately counted or to provide truthful information to authorities. Furthermore, these early efforts rarely attempted a complete enumeration of the population. Instead, they often focused only on specific categories, such as heads of households or males of military age, rather than capturing a representative sample of the entire society. These limitations meant that premodern data remained fragmentary and lacked the comprehensive, systematic approach that characterizes modern demographic research.1