Age × stage-classified demographic analysis: a comprehensive approach

Area of Science:

• Ecology
• Demography
• Population Biology

Background:

• Traditional demographic models focus on either age or stage, limiting comprehensive analysis.
• Previous research has explored age-stage classification sporadically since the 1960s.
• Integrating age and stage provides a more complete picture of population dynamics.

Purpose of the Study:

• To develop a comprehensive theory for demographic analysis of populations classified by both age and stage.
• To incorporate age- and stage-specific vital rates into demographic analysis using matrix population models.
• To present a complete analysis of population dynamics, including life table functions and population growth.

Main Methods:

• Utilized the vec-permutation formulation of multistate matrix population models.
• Incorporated age- and stage-specific vital rates into demographic analysis.
• Analyzed cohort results, including survivorship, fertility, longevity, and life disparity.

Main Results:

• Presented a complete set of population dynamic results, including growth rates, structures, and reproductive statistics.
• Demonstrated that age and stage structure represent unobserved heterogeneity from each other's perspective.
• Showcased the partitioning of demographic variance into age and stage contributions.

Conclusions:

• Age × stage-classified demography offers a more detailed and accurate understanding of population dynamics.
• These models are amenable to sensitivity analysis, crucial for future ecological and human demographic studies.
• The integration of age and stage is essential for advancing demographic theory and application.