Why are estimates of the pre-Columbian population of North America uncertain?

Estimates of the pre-Columbian population of North America are highly uncertain, with scholarly figures ranging from approximately 900,000 to 18,000,000 individuals. This wide disparity arises from several methodological and historical challenges:1

• Reliance on Assumptions: Early demographic models often relied on limited historical accounts, such as fur traders' reports of the number of warriors in a tribe. Because these accounts rarely recorded the total population, researchers must make assumptions about the ratio of women, children, and elders per warrior. Small variations in these initial presumptions can lead to massive differences when extrapolated over generations.1
• Disjunctions in Evidence: Critics of high-population models, such as those proposed by Henry Dobyns, point to discrepancies between theoretical models and physical evidence. For example, the number of houses found at archaeological sites often suggests a smaller population than what demographic recovery models predict.1
• Impact of Disease: There is significant debate regarding the timing and severity of European-introduced diseases. While some scholars argue that epidemics were devastatingly widespread, others suggest that the potential for pre-Columbian contact—such as the Norse presence at L’Anse aux Meadows—means that Indigenous populations may have suffered from introduced diseases long before 1492, complicating efforts to calculate founding populations.1